tag:blogger.com,1999:blog-86894877401076921352024-03-13T05:47:41.100-07:00Red Spade AudioWelcome the Red Spade Audio blog where you'll find DIY audio projects, articles and inspiration for your audio system.Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.comBlogger493125tag:blogger.com,1999:blog-8689487740107692135.post-62712922514774120672023-12-06T21:55:00.000-08:002023-12-06T21:58:09.847-08:00Why I stopped using T-nuts and what you should use instead<p>It only takes one DIY project gone wrong to realise what a big mistake it can be to use Tnuts to secure a driver. Or you might be stubborn like me and it might take several incidents before you give up on Tnuts forever!<br /><br />Now I'll admit, I still have uses for them. If you need to secure castors to dollies that carry heavy loads, Tnuts are ideal. But for mounting drivers, there is a huge potential problem. </p><p>To illustrate, here's a problem Tnut removed from a subwoofer:</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhZgy8txf_QglU-bUtsN9dBnva2SrtX_F8zOjDN-w5se3Q53R9coVJrgcyVys-Qhelv8ChhxBRReoVE5ZMUABmh8_FTkWtvnetSPXuBTYQPbbNpM9lcxccl9e8Qrzt_MziporcJthjyDSBkugt_u2Ua_44cvYYWBd8m1UUllPEiS3jYAODaUcgs6M0AEazU/s550/tnut-vs-insert.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="217" data-original-width="550" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhZgy8txf_QglU-bUtsN9dBnva2SrtX_F8zOjDN-w5se3Q53R9coVJrgcyVys-Qhelv8ChhxBRReoVE5ZMUABmh8_FTkWtvnetSPXuBTYQPbbNpM9lcxccl9e8Qrzt_MziporcJthjyDSBkugt_u2Ua_44cvYYWBd8m1UUllPEiS3jYAODaUcgs6M0AEazU/s16000/tnut-vs-insert.jpg" /></a></div><br /> <p></p><h4 style="text-align: left;">What happened?</h4><p>In this example, the Tnut became dislodged. When you insert the hex head screw, it can easily push the Tnut out. In this example, I had actually drilled two different sizes of hole into the MDF to prevent this from happening. It didn't matter. It happened anyway. The weakness of Tnuts is that they resist twisting fairly well, but if they are pushed out by the screw, you're in trouble. <br /><br />Now, you might be thinking you can just unscrew the driver. Not so. Now you have one screw that can't be easily undone. <br /><br />Next you try with a spanner to pull the head outwards, so that Tnut prongs will bite back in. Often what actually happens at this point is not what you're hoping. It simply cuts a circular trench and the Tnut digs in and keeps spinning, like a car that is now bogged in mud. Sometimes you have to cannibalise the cabinet to gain access to the Tnut. You might be thinking a hand to hold the Tnut is enough. Again, not so! A tight grip with pliers is required. The Tnut can also jam. </p><h4 style="text-align: left;">The alternative?</h4><p>The better choice is also in the photo - threaded inserts. Just like Tnuts, they are installed on the rear side of the baffle, on the surface opposite the head. They are easiest to insert prior to gluing up the baffle to the cabinet. You'll need an allen key or hex head bit in the cordless driver. <br /></p><h4 style="text-align: left;">What makes them better?</h4><p>In short, they don't tend to fall out. A Tnut resists rotation much more than it resists being pushed out by the screw on assembly. A threaded insert adequately resists rotation but more importantly, it has a thread which bites in to the hole in which it is inserted. The thread means it won't come out unless you bash it out with a hammer. <br /></p><h4 style="text-align: left;">Still not convinced to ditch Tnuts?</h4><p style="text-align: left;">Ok a few more horror stories. Sure, I'll play the clown in the interests of public education. <br /><br />I was working on a prototype build for a custom church organ speaker. Yes, it happened. Tnut came loose and it prevented me from removing the driver. I was able to get some access inside the box. To hold the Tnut so I could unscrew it, I had to make up a quick jig. It was quite some time ago, so I'm not sure if it took 3 hours or just felt like 3 hours. <br /><br />In another episode, I was helping a client assemble a kit where I supplied drivers and flat pack and he had built it. In this case, it was a long trip and that's when you don't want anything to go wrong. I had a calibration job to get done - the last thing I want is a Tnut coming loose. Yes - it happened!<br /><br />There are many more stories like this. I'd like to say I learn quickly. In reality, it's often through mistakes.<br /></p>Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com0tag:blogger.com,1999:blog-8689487740107692135.post-14230642005508616142022-03-23T20:23:00.003-07:002022-03-23T20:25:26.017-07:00Specialist subs - moving beyond sealed and ported subs<div style="text-align: justify;">When it comes to mass produced subwoofers, it makes sense to manufacture generalist subs. In 2 channel systems, this will mean moderately sized sealed subs. For home theatre, it usually means ported subs. These conventional designs are good all-rounders. They can easily cover 20 Hz - 80 Hz and even dig deeper than that. <br /></div><p style="text-align: justify;">So what happens when you want to go beyond what you can get out of one or two fairly conventional subs? If you're buying from the conventional hifi retailers, the price goes up quickly as you start to move into 15" or 18" subs. You pay a lot more but do you actually get that much more?</p><p style="text-align: justify;">In over a decade now of going into rooms and testing how they perform, one thing has become clear. You can do a lot better, when you know your room. Once you do understand your room acoustics and how the sub will perform in different positions in your room, this gives rise to some different goals. Many people assume that all subs in a system should be the same so that one doesn't bottleneck the system. In reality, the opposite is often true. When you have more than one sub, often they are not all doing the same job. <br /></p><h4 style="text-align: left;">The heavy lifter</h4><p style="text-align: justify;">In some rooms, you may have one position that is ideally suited to very low bass. It's usually due to having the best room gain in the bottom octave. It could also be because this particular position allows a larger sub than other locations, which might be limited by things like windows, doors, speakers, furniture. In a multi sub set up this sub doesn't necessarily need to cover the upper bass. This type of sub suits a ported, bandpass or horn alignment. Where this type of sub is used, normally it will handle the lower bass without any help from the other subs. Hence, it will allow any other subs to be smaller.</p><h4 style="text-align: justify;">The infill sub</h4><p style="text-align: justify;">If this is the second sub to be paired with a heavy lifter, it won't need to cover the low end. That means generally it can be more compact. Typically an infill sub will cover 40 - 80 Hz. It might be a conventional sub with a standard hifi driver in a sealed box. Its purpose is to fill in dips caused by room modes, where we can't find a single position that avoids all dips. </p><h4 style="text-align: justify;">The thumper</h4><p style="text-align: justify;">This is the name that I give to a sub that functions as an infill but that is designed for higher output. We can achieve this with a bandpass design, giving up some extension to get higher sensitivity. This is the case with a recently designed sub that I cal "lil thumper." It has 92 dB sensitivity. We can also achieve this using pro drivers, where the sensitivity might range from 93 - 97 dB. <br /></p><h4 style="text-align: justify;">The stealth infill sub</h4><p style="text-align: justify;">Sometimes we need an infill sub to fill in some dips, but we might need that sub in a position that might localise. This can happen where the sub is located around the back of the room and quite close to the listening position. If you aren't careful, you may be able to tell where the sub is located and that can be distracting. For this type of sub we have to be careful to avoid any features that would give away the location of the sub. This can come from air leaks, turbulent ports that chuff, ports with port resonances above the passband or horns with ringing above the passband. Even a sealed sub, which by design avoids all these things, can still localise. <br /><br />This type of sub is tricky, especially where it must fill in dips in the mid and upper bass. Extra care must be taken. <br /><br />Does this all sound confusing? Watch this space, as I will be adding some example that will make the use of these specialist subs more clear. <br /></p>Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com0tag:blogger.com,1999:blog-8689487740107692135.post-45641814691149446592022-03-16T01:33:00.012-07:002022-03-18T00:53:09.604-07:00What happens when a bass box is too large<div class="separator" style="text-align: justify;"></div><p style="text-align: justify;">Recently we had a client bring in a custom loudspeaker cabinet which had been built for some vintage drivers, featuring a 15" woofer. Much to my suprise, initial modelling indicated an enclosure that is much too large. More commonly, cabinet size is compromised and smaller than ideal. We usually want a box to be smaller than it could be. Hence this is a surprise when it goes the other way. This prompts a fair question: how do we decide how large a ported enclosure should be? </p><p style="text-align: justify;"></p><div class="separator" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="526" data-original-width="522" src="https://blogger.googleusercontent.com/img/a/AVvXsEhhY85dUtHN3L1guUA6BpvTh5eaMR7Z8xnDCmShIGwevizo8pRmlwdnwEc5c9Xng31caLyK6xLHVwIIfIPUkVflSwyfuBMxPqZ9T_JO2QSIFD1zQmKgDfLAXnpAkBByjazNspZmBQiGwsah2huZakXXNVK6etZTrrgAzimJVc0BgSUxC4MiXt_kXkOklQ=s16000" /> </div><p></p><h4 style="text-align: justify;">How low can you go? </h4><div style="text-align: justify;"> </div><div style="text-align: justify;">First we consider the maximum bass extension that we can achieve with a given driver. Typically we start with the driver free air resonance (fs). This provides an initial guess at the potential bass extension. Of course, the actual potential depends on all parameters. So the quick way to find out is to model a standard alignment such as Chebyshev. Shown white in the plot below. <br /></div><div style="text-align: justify;"><br /></div><div class="separator" style="clear: both; text-align: justify;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEiMrqqy3eeQcNOskmrwji9Fbluelh9rK1zVA6Ia0ZSE7wTTLrZW7vxpiInSxIl-AFKaWW_aaK4sqOYDYjfrlzcmhBksB0ofP4LYRMDfai1OLUb39gLnFviavLVxeFkT6pNcYvOJkHwJQvw77sC8UoD0uyqri4B9ftNBsD3mv1Qsg3AX5eUp5BN45acj-g=s523" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="523" data-original-width="520" src="https://blogger.googleusercontent.com/img/a/AVvXsEiMrqqy3eeQcNOskmrwji9Fbluelh9rK1zVA6Ia0ZSE7wTTLrZW7vxpiInSxIl-AFKaWW_aaK4sqOYDYjfrlzcmhBksB0ofP4LYRMDfai1OLUb39gLnFviavLVxeFkT6pNcYvOJkHwJQvw77sC8UoD0uyqri4B9ftNBsD3mv1Qsg3AX5eUp5BN45acj-g=s16000" /></a></div><div style="text-align: justify;"><br /></div><div class="separator" style="clear: both; text-align: justify;">Green shows an EBS alignment, in which we give up 3 dB of sensitivity to achieve lower bass extension. This type of alignment involves a trade-off in which we give up maximum output in order to achieve lower bass. We should think carefully about this in this instance, as we're dealing with a 12" driver with limited output at very low frequencies. It may be worthwhile in small rooms with considerable gain. <br /></div><div class="separator" style="clear: both; text-align: justify;"> </div><div class="separator" style="clear: both; text-align: justify;">The next example (red) shows a compromise we might make to downsize the cabinet. The white alignment is 90L but we can get it down to a more modest size (65L) in this example without giving up much.</div><div class="separator" style="clear: both; text-align: justify;"><br /></div><div class="separator" style="clear: both; text-align: justify;">So far these are all workable choices, with typical trade offs with sensitivity, extension and size. But here is an example of a badly designed bass box - one which is larger than beneficial. </div><div class="separator" style="clear: both; text-align: justify;"><br /></div><div class="separator" style="clear: both; text-align: justify;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEhjypbVd_xZEmKDgMf2o25mRjyScbm294zcKS2BnPGqctX79ol8mXJGiWwGc5DTcVB4D2uVXbLOsVXSgazdxqR9cicgxweGBO2qHYuQSc_DiShmcIJNqroGSH9L485F5Rx4dBjYD31nJiCf3H8-xtSrRwrsO4Q_473UgaVAhtDjhIsNoPXfY_OsEyymwA=s524" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="524" data-original-width="515" src="https://blogger.googleusercontent.com/img/a/AVvXsEhjypbVd_xZEmKDgMf2o25mRjyScbm294zcKS2BnPGqctX79ol8mXJGiWwGc5DTcVB4D2uVXbLOsVXSgazdxqR9cicgxweGBO2qHYuQSc_DiShmcIJNqroGSH9L485F5Rx4dBjYD31nJiCf3H8-xtSrRwrsO4Q_473UgaVAhtDjhIsNoPXfY_OsEyymwA=s16000" /></a></div><div class="separator" style="clear: both; text-align: justify;"> </div><div class="separator" style="clear: both; text-align: justify;">Blue - an oversized bass box. In this case, the cabinet is 300L. </div><div class="separator" style="clear: both; text-align: justify;"><br /></div><h4 style="text-align: justify;">What's wrong with this box?</h4><p style="text-align: justify;">Of course, there is always the practical issues like WAF, aesthetics and the extra challenges that go with very large boxes that are hard to handle and fit in your room. Aside from these issues, we also have a box that is hard to properly brace without it becoming extremely heavy. <br /><br />Like with the EBS cabinet, we've given up some midbass punch, but we've also got an undesirable peak around tuning. <br /></p><div style="text-align: justify;"><h4>What can we do with an over sized bass box?</h4><h4> </h4></div><div style="text-align: justify;">After the box is built, we can sometimes rescue it by changing the tuning. </div><div style="text-align: justify;"><br /></div><div class="separator" style="clear: both; text-align: justify;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjqV2exXtxka9ay3wHlC-fxuzwmlx_wVkI87a_EA-NnUuVYGAOBC8WJxcPOVCV2PomUUchn0f3RjwGCFZUweCCRdKsrHXpz4lIJY0utTpASp_F61fwvf2GyipPtwaJ47P1-WCXurMj_WiFWokQXv37NLK-XzRtGj4hBAexYX-TXfdohXs_8Xjdo8Vm20A=s523" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="523" data-original-width="522" src="https://blogger.googleusercontent.com/img/a/AVvXsEjqV2exXtxka9ay3wHlC-fxuzwmlx_wVkI87a_EA-NnUuVYGAOBC8WJxcPOVCV2PomUUchn0f3RjwGCFZUweCCRdKsrHXpz4lIJY0utTpASp_F61fwvf2GyipPtwaJ47P1-WCXurMj_WiFWokQXv37NLK-XzRtGj4hBAexYX-TXfdohXs_8Xjdo8Vm20A=s16000" /></a></div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">Here, all 3 cabinets have the same volume (300L) but different port tuning. We can remove the peak at tuning by lowering tuning by 2 Hz. If we tune higher, the peak gets worse (dark blue). </div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">So we can see that if your cabinet is larger than required for a balanced design, the best passive solution is to lower the tuning and effectively convert to an extended bass shelf design. If the extra extension isn't wanted, then there are two choices: EQ or rebuild. If EQ is used, we can overcome any sound quality issues and we expect to achieve higher SPL and hence more dynamic range. On the other hand, if we rebuild the cabinet, it's likely that we can end up with a more desirable result. The new box can be more aesthetic and we can also include more cabinet bracing, given that this tends to reduce net volume. <br /><br /><h4>SPL vs extension</h4></div><div style="text-align: justify;"> </div><div style="text-align: justify;">Quite commonly, audiophiles who don't understand the SPL cost of bass extension often will choose bass extension over maximum output. This is why we now have the modern trend of subs with impressive extension that actually lack the dynamic range required to fully appreciate it. There is actually no point in having bass extension to 12 Hz if you don't have enough SPL capability to actually appreciate that bass extension. <br /><br />So let's compare the above alignments in terms of their actual SPL. In each case, power level is chosen to reach xmax above tuning. </div><div style="text-align: justify;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEh98TIpiAlvYAh2aWPdju3rMsOBY6Tb9xskStsleqOmersLspYMidrz1ipEiSrbXS4hti6qNtqTwKHzTV1YAUgdjHgPZyNFVDaMo4gYLW-X0kxeWaTNj8MKEUbdjv83-VXcEYZHHDnYoVrb3BUJlHOL6GvlbiGQ5_4PKY_bIjmjrDRHLwUdletFQAqS4Q=s532" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="370" data-original-width="532" src="https://blogger.googleusercontent.com/img/a/AVvXsEh98TIpiAlvYAh2aWPdju3rMsOBY6Tb9xskStsleqOmersLspYMidrz1ipEiSrbXS4hti6qNtqTwKHzTV1YAUgdjHgPZyNFVDaMo4gYLW-X0kxeWaTNj8MKEUbdjv83-VXcEYZHHDnYoVrb3BUJlHOL6GvlbiGQ5_4PKY_bIjmjrDRHLwUdletFQAqS4Q=s16000" /></a></div><br /><div style="text-align: justify;">Red: 65L cabinet tuned at 20 Hz with 210 W<br />White: Chebychev alignment 90L tuned to 19 Hz with 160W </div><div style="text-align: justify;">Green: EBS alignment 225L tuned to 15 Hz with 83W </div><div style="text-align: justify;">Blue: Oversized cabinet 300L tuned to 14 Hz with 67W</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">Excursion - we can see that all these subs would require a rumble filter below tuning</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEiWL0DqwV-Fcpc6DIFFcgIVhFwvkaCtTrK2NGOoxhU6eA41HW9gCKpOn0djUKtyAkfILVKEmk-sxgPRWnoUJqwGK5lg1MwLDaLfZ9-B-6Mxbm5Bim2zVgyLOWi6j_O6GesAIQk4_jdgKBEDHAhh2bSq5YQfSulzrQh_fBDoHJ1axX3T934PNpoqJ4TKNg=s535" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="389" data-original-width="535" src="https://blogger.googleusercontent.com/img/a/AVvXsEiWL0DqwV-Fcpc6DIFFcgIVhFwvkaCtTrK2NGOoxhU6eA41HW9gCKpOn0djUKtyAkfILVKEmk-sxgPRWnoUJqwGK5lg1MwLDaLfZ9-B-6Mxbm5Bim2zVgyLOWi6j_O6GesAIQk4_jdgKBEDHAhh2bSq5YQfSulzrQh_fBDoHJ1axX3T934PNpoqJ4TKNg=s16000" /></a></div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">In the case of this specific sub, I'd argue the larger cabinets are not good choices for all but very small rooms with a large amount of gain. 103 dB modelled at 16 Hz is not a very good result. In many larger rooms in Australia, the low bass output could be very unimpressive. <br /><br />On the other hand, the much smaller 65L cabinet achieves 110 dB in the midbass. If we carefully optimise position, this sub will likely offer impressive performance in a much more attractive package. The 2 dB greater output compared to the larger version will actually sound about one third louder. Bigger is not always better!<br /></div>Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com0tag:blogger.com,1999:blog-8689487740107692135.post-82645145344728004512022-01-05T03:39:00.008-08:002022-01-05T13:29:25.318-08:00Lil Thumper build<div><div class="separator"></div><div style="text-align: justify;"></div><p style="text-align: left;"></p><p style="text-align: left;"></p><p style="text-align: left;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEhz_0YuxHUYIbajHKjREQ9k-HRwlZFo8Yefv6rZUnYcu1qXOHy7huocF3is_Iafa4lxK5H6NKOZyqOjC6hCWdajVSYlnKvl3_rrOHA5cy_TO2OYxL88spqFy5m9cPKAza7gnmZm4FczahPx5WfAbXJpN-tKtD8LuM6-Tbg4FxI4qmOpQbz2QdMdtywqUg=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="265" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEhz_0YuxHUYIbajHKjREQ9k-HRwlZFo8Yefv6rZUnYcu1qXOHy7huocF3is_Iafa4lxK5H6NKOZyqOjC6hCWdajVSYlnKvl3_rrOHA5cy_TO2OYxL88spqFy5m9cPKAza7gnmZm4FczahPx5WfAbXJpN-tKtD8LuM6-Tbg4FxI4qmOpQbz2QdMdtywqUg=s16000" /> </a>First the internal baffles are glued together and Tnuts are tapped into place. </p><p style="text-align: left;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEgLIsGcbGWCEMpqpHpppZxr1JJNpsqe40M30Qp6hm5q7sPYK2xcFeORbnE4Kk7SjZNopLTYFMiw5iCMKKXCcGonZb2Nn7wD3OJTgZJCs6bfWaxHlOs3pPQjFd3yAO2GlONt3oyhgTd-Ry4UdZr9G3VfbgEsnYAECOHBs7DbQfKmMdk4goxlw_sJlnYRbQ=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="531" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEgLIsGcbGWCEMpqpHpppZxr1JJNpsqe40M30Qp6hm5q7sPYK2xcFeORbnE4Kk7SjZNopLTYFMiw5iCMKKXCcGonZb2Nn7wD3OJTgZJCs6bfWaxHlOs3pPQjFd3yAO2GlONt3oyhgTd-Ry4UdZr9G3VfbgEsnYAECOHBs7DbQfKmMdk4goxlw_sJlnYRbQ=s16000" /></a></p><p style="text-align: left;">It's a good idea to seal the internals before assembly. Later, it will be difficult to access. Here I'm using Duratex rolled on. A heat gun speeds up the process so that we can move on quickly. </p><p style="text-align: left;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEhiAVQVuSN7tnjTTAGC0RStWAYjHzOfFCZTEwbdM5WTKfcjd_VFyuAied11h-gqo-OMKxhqjTnwxobiC-_fy_hFxZQg433tRTS0cl-8zhfy5OyJESEoSpslvT1bjUuy0rh17j5K-OWlifkLMpcfhhPGCrOLNAWEjas4xehpV4qrDa2-lHQmhoAUY1Zyjw=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="338" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEhiAVQVuSN7tnjTTAGC0RStWAYjHzOfFCZTEwbdM5WTKfcjd_VFyuAied11h-gqo-OMKxhqjTnwxobiC-_fy_hFxZQg433tRTS0cl-8zhfy5OyJESEoSpslvT1bjUuy0rh17j5K-OWlifkLMpcfhhPGCrOLNAWEjas4xehpV4qrDa2-lHQmhoAUY1Zyjw=s16000" /></a></p><p style="text-align: left;">Now the back and braces are laid out. You can see the braces sit into machined trenches. <br /></p><p style="text-align: left;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjl56pJc0jR88zrM2QZBQWDyKBmLLIZkkaTQQ5rIpcQrWlhtpDj12Ec0-SpIP4G3M2gOveoGnj7dakYueTXWTSIEi_5OijupXbS83MDXS4a_nXjs_yVMJqwqSvCrKb0BTSZhj1keANY6XPt6haRr-z9d6OJ3KNnMvrLaNvrB49sILtwlXQdIYVu_6yTKA=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="188" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEjl56pJc0jR88zrM2QZBQWDyKBmLLIZkkaTQQ5rIpcQrWlhtpDj12Ec0-SpIP4G3M2gOveoGnj7dakYueTXWTSIEi_5OijupXbS83MDXS4a_nXjs_yVMJqwqSvCrKb0BTSZhj1keANY6XPt6haRr-z9d6OJ3KNnMvrLaNvrB49sILtwlXQdIYVu_6yTKA=s16000" /></a></div><div class="separator" style="clear: both; text-align: justify;"> These braces are laid down first. <br /></div><div class="separator" style="clear: both; text-align: justify;"> </div><div class="separator" style="clear: both; text-align: justify;"><div class="separator" style="clear: both; text-align: left;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEj-zmKk3znsrHGt72clMMznkYen5zAoQtFrx_6eTjbe8egHtH4fK6fNeoC-adN13KI7mUCoh7Osf9OAbRhFkMHdGdvmxkt3eOZ04E-xRe7jlNSUQUrpUvOQFpNgfEU5hirS0uvhhSL3g0cypQHDwrNmo_8MyC7D2AML3YoQv2_h2-N_IOVcxYrLsJF-1w=s550" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="294" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEj-zmKk3znsrHGt72clMMznkYen5zAoQtFrx_6eTjbe8egHtH4fK6fNeoC-adN13KI7mUCoh7Osf9OAbRhFkMHdGdvmxkt3eOZ04E-xRe7jlNSUQUrpUvOQFpNgfEU5hirS0uvhhSL3g0cypQHDwrNmo_8MyC7D2AML3YoQv2_h2-N_IOVcxYrLsJF-1w=s16000" /></a></div><br /></div><div class="separator" style="clear: both; text-align: justify;"></div><div class="separator" style="clear: both; text-align: justify;">The next bracing pieces lock into the others. When combined with the trenches on the back panel, this ensures all the braces are located in the correct positions. No guess work involved.</div><div class="separator" style="clear: both; text-align: justify;"> </div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEi5nlUZOUq6_E-Pf9v5a0cdxDmB_TZuvQCrteWIg6PVLP8aYXmbB7jry36JMqMmx5dkqMs6FBfzHVhcc0UyLAXUZX0KL-YsnrvRPtxoyiBtGlmdxmRkAQ9VAdTJOMPu9vLy_Td5J5oGu02kSqdtfIhevRS1WxyDTVDlPnHYmqI7GXj3wSWgRjUfEF4fcA=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="477" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEi5nlUZOUq6_E-Pf9v5a0cdxDmB_TZuvQCrteWIg6PVLP8aYXmbB7jry36JMqMmx5dkqMs6FBfzHVhcc0UyLAXUZX0KL-YsnrvRPtxoyiBtGlmdxmRkAQ9VAdTJOMPu9vLy_Td5J5oGu02kSqdtfIhevRS1WxyDTVDlPnHYmqI7GXj3wSWgRjUfEF4fcA=s16000" /></a> <br /></div><div class="separator" style="clear: both; text-align: justify;"> Braces are now secured to the back panel. <br /></div><div class="separator" style="clear: both; text-align: center;"> </div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEilpPkZWE43-8BMT3HNpJUS9hGrT89I41-O4ShQBJdJHUlo7O_ovNGZVLZvm1BrgYg40ue771G1vMGsOvV5un2cEuG_71MmCSGjNwPy4noGW7HU5FA42HPG2wEdi51Wgf-ywjqxRclJfuYVFd5BtQFilG6zttO_Pl2ijZK4XkVnH7-1-JOUmGUhmKMMHw=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="400" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEilpPkZWE43-8BMT3HNpJUS9hGrT89I41-O4ShQBJdJHUlo7O_ovNGZVLZvm1BrgYg40ue771G1vMGsOvV5un2cEuG_71MmCSGjNwPy4noGW7HU5FA42HPG2wEdi51Wgf-ywjqxRclJfuYVFd5BtQFilG6zttO_Pl2ijZK4XkVnH7-1-JOUmGUhmKMMHw=s16000" /></a> <br /></div><div class="separator" style="clear: both; text-align: justify;">Lining is glued in place. Here I'm using high density panels that we also use in bass traps. Normal speaker box lining is not quite so effective at damping port resonances. I've found that thicker and higher density material works much better and ensures the output is clean.<br /></div><div class="separator" style="clear: both; text-align: center;"> </div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEisWK7UO0MS8fYRymt3qwhZXA7vnBAGuXgm_7dT_cwXSQL17migvmr20VFp7xIQlW9Jwzt9DcEKdBhROormwyRuecqr_3S8p8x_O2fLv_xMVA2sst_MDy-weKdF4Ek4RtVtJGunPBmva8YLpcDI-ns-LqidNB160p35bnjMc2qYNWRz5wMhfQzyxIWqng=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="434" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEisWK7UO0MS8fYRymt3qwhZXA7vnBAGuXgm_7dT_cwXSQL17migvmr20VFp7xIQlW9Jwzt9DcEKdBhROormwyRuecqr_3S8p8x_O2fLv_xMVA2sst_MDy-weKdF4Ek4RtVtJGunPBmva8YLpcDI-ns-LqidNB160p35bnjMc2qYNWRz5wMhfQzyxIWqng=s16000" /></a> <br /></div><div class="separator" style="clear: both; text-align: justify;"> The baffle is laid out and now glue is applied. <br /></div><div class="separator" style="clear: both; text-align: center;"> </div><div class="separator" style="clear: both; text-align: justify;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEgY3QsijgN_NW_HdBaata0IP1r7_Ovh72wl4bue6k-ctzfS_AFkJ1w3uqY6obXLsFTgtjQ1t9B6hv_Bxi8EdEd5INiPeGQnhsVNUwPRVvJY4za8Z4x81sASjb8mubD2KgCd56SZr8zdHS03DnPkMdLaBtdbbin7BdKhBNiGGJjABh6PeH5xiQQCjhP_XQ=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="366" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEgY3QsijgN_NW_HdBaata0IP1r7_Ovh72wl4bue6k-ctzfS_AFkJ1w3uqY6obXLsFTgtjQ1t9B6hv_Bxi8EdEd5INiPeGQnhsVNUwPRVvJY4za8Z4x81sASjb8mubD2KgCd56SZr8zdHS03DnPkMdLaBtdbbin7BdKhBNiGGJjABh6PeH5xiQQCjhP_XQ=s16000" /></a> Lowering the internal baffles into place. <br /></div><div class="separator" style="clear: both; text-align: center;"> </div><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEhSnbpqnHnOsQLhs6Iyqnm6EYGRPh33qxJnC_mNHIgUFSj6n_dRXs-p9tTjaKjfvGZ4E1MYabaAcpmK_kfVPK3IN20xxZP3P5bwqxn_Knh_ezgpmB5pcYTVBuj5FYpWtpchqMvJpdr-LXtNQ34pZ5NUktXZ11p3FhgBNRZ6IY5273yTo0uXkdwSCJ7_WA=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="428" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEhSnbpqnHnOsQLhs6Iyqnm6EYGRPh33qxJnC_mNHIgUFSj6n_dRXs-p9tTjaKjfvGZ4E1MYabaAcpmK_kfVPK3IN20xxZP3P5bwqxn_Knh_ezgpmB5pcYTVBuj5FYpWtpchqMvJpdr-LXtNQ34pZ5NUktXZ11p3FhgBNRZ6IY5273yTo0uXkdwSCJ7_WA=s16000" /></a> <br /></div><div class="separator" style="clear: both; text-align: justify;">The first side panel is glued into position. <br /></div><div class="separator" style="clear: both; text-align: justify;"> </div><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEig6nbZeV4MTfkBaB0G5Tk7EpKjaPJT7cvHm4M_P6BpWnQ1ahaN1LVo_-iMzhh5DDHM5YT4ZxTy961FnSXNh_Pxgyg6Riqipr2GTyZjYM4A7d6VHiYf81OI-Sf_PciVdLDIXAEnNeXQoEtheZIdIHWTqmHJM05toC1oQqdgLovzeQHmd036eYlzoQi3CA=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="476" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEig6nbZeV4MTfkBaB0G5Tk7EpKjaPJT7cvHm4M_P6BpWnQ1ahaN1LVo_-iMzhh5DDHM5YT4ZxTy961FnSXNh_Pxgyg6Riqipr2GTyZjYM4A7d6VHiYf81OI-Sf_PciVdLDIXAEnNeXQoEtheZIdIHWTqmHJM05toC1oQqdgLovzeQHmd036eYlzoQi3CA=s16000" /></a> <br /></div><div class="separator" style="clear: both; text-align: justify;">The second side is glued into place. <br /></div><div class="separator" style="clear: both; text-align: center;"> </div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEhZ1CcFaI952kOnkJCv15jD5feAK3ldUPseZzBq3ZBUAWbzBuZ-vxt4O-NGBzlP8W5PwpWcNonCK-slMkCHi3Mu92wWbCE9mfpoEB4MsfFlM9tDMT4hSvVN9LB3EgCoGHx045Yhr6b6zXVWKcuOArs_uGoqu3Wnn0B6iyV2dajxIjGxoyx-O_8jf4UAbA=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="501" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEhZ1CcFaI952kOnkJCv15jD5feAK3ldUPseZzBq3ZBUAWbzBuZ-vxt4O-NGBzlP8W5PwpWcNonCK-slMkCHi3Mu92wWbCE9mfpoEB4MsfFlM9tDMT4hSvVN9LB3EgCoGHx045Yhr6b6zXVWKcuOArs_uGoqu3Wnn0B6iyV2dajxIjGxoyx-O_8jf4UAbA=s16000" /></a> <br /></div><div class="separator" style="clear: both; text-align: justify;">Now with the second side in place, the clamps are moved. <br /></div><div class="separator" style="clear: both; text-align: center;"> </div><div class="separator" style="clear: both; text-align: justify;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEgFLI64EJpjJr4fLDP2WtRFe99T0K3FCO4bsgRu3IMdfiZwHYkBegoxWZcphVAZ_FLWEqmpQUsJ1sV6Y7BvQPlCUdVJbp4gV3MHKr-mvCiL4t2M26JTAExejGpAT5DW8yhQv6JVIA4Nj5F3KKb6G7eA3S8dpCTGk0IFNfKEEUfyyHjhKvk2Nv3JFzGGxw=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="444" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEgFLI64EJpjJr4fLDP2WtRFe99T0K3FCO4bsgRu3IMdfiZwHYkBegoxWZcphVAZ_FLWEqmpQUsJ1sV6Y7BvQPlCUdVJbp4gV3MHKr-mvCiL4t2M26JTAExejGpAT5DW8yhQv6JVIA4Nj5F3KKb6G7eA3S8dpCTGk0IFNfKEEUfyyHjhKvk2Nv3JFzGGxw=s16000" /></a> Solid timber braces put into place. These will be glued in place later. The absorber panels are already glued in place. Later, access is impossible. The unpainted parts are the trenches on the sides, top and bottom.</div><div class="separator" style="clear: both; text-align: center;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEiXF3XJNmUYiU-TYdQmZe-7KfESaDadm9nmR6Jjw742VMX-ueWiB6u6YO6LvnyXMUoF9RhxCZkJu1zqUWXp35CoWp6jSKUyIbmU4MASpgdc_e9oHiXs_j7bzFwOgO4ryGXSb1Xx5c_XLybitPYIlL1crKztMBZP-qi-yjBpjYx-YbKibkX94R2L0zp7hQ=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="457" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEiXF3XJNmUYiU-TYdQmZe-7KfESaDadm9nmR6Jjw742VMX-ueWiB6u6YO6LvnyXMUoF9RhxCZkJu1zqUWXp35CoWp6jSKUyIbmU4MASpgdc_e9oHiXs_j7bzFwOgO4ryGXSb1Xx5c_XLybitPYIlL1crKztMBZP-qi-yjBpjYx-YbKibkX94R2L0zp7hQ=s16000" /></a></div><div class="separator" style="clear: both; text-align: justify;">Top panel clamped into place. <br /></div><div class="separator" style="clear: both; text-align: center;"> </div><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjdxoqxbpBch2obfbhP2m6Kcn-qNX3YTnpAs9csnm0CoT4Oy--RA8CCmHSy8Vkv_F40onTZgIDv3nrIJIJ8w0bOyf4y65XQb_UAfjWeUF9groR04Pb-GZOh171g-gbWmZP62jdC43rNHWOctiihlucwYKejx-q4Byxb3L6_bhgEI4AJGf2Tk1OypfhJ3w=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="341" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEjdxoqxbpBch2obfbhP2m6Kcn-qNX3YTnpAs9csnm0CoT4Oy--RA8CCmHSy8Vkv_F40onTZgIDv3nrIJIJ8w0bOyf4y65XQb_UAfjWeUF9groR04Pb-GZOh171g-gbWmZP62jdC43rNHWOctiihlucwYKejx-q4Byxb3L6_bhgEI4AJGf2Tk1OypfhJ3w=s16000" /></a></div><div class="separator" style="clear: both; text-align: justify;">This is a dry fit to show the internal structure. <br /></div><div class="separator" style="clear: both; text-align: center;"> </div><div class="separator" style="clear: both; text-align: justify;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEgoQ06fRDgtt_uvuRnXeFf_hrHRC49KKVudrfKbSMbgtQlymgJnP5rAFkfaJS2lyyyPjEI1L-z_0qpDcxANQpj3SeKlBZZj1DKhG___UwcjVM_110q--r3SAaGejvb-vO4ewEwQX5EOnlWVMPpk8NbgXAD7oYckglwRPH3jmHoUX0zp5aOuv89PUn7K_A=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="385" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEgoQ06fRDgtt_uvuRnXeFf_hrHRC49KKVudrfKbSMbgtQlymgJnP5rAFkfaJS2lyyyPjEI1L-z_0qpDcxANQpj3SeKlBZZj1DKhG___UwcjVM_110q--r3SAaGejvb-vO4ewEwQX5EOnlWVMPpk8NbgXAD7oYckglwRPH3jmHoUX0zp5aOuv89PUn7K_A=s16000" /></a> I haven't taken photos of the assembly of the solid timber braces and the port, which has four pieces, with round overs on both inlet and outlet. There is also a brace not shown. This part of the build was fairly involved, with many panels being secured in rapid succession. It's difficult to handle the camera when dealing with polyurethane glue. </div><div class="separator" style="clear: both; text-align: center;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjvk-wlGS9SJdR0F0BdQybvyPQSb5WYHlQcXxXOJxc75txxCJpbpUfgIA4m-qZye6n-ImaEc18rZx0YSeJbTzP_meIXdbUQ8pIs4jrqB1HaNqVFPQcPrVuHD36gYqxNK3wUsSmHMB-q0RfXDYGgoQIAZeIHW406qG8gby7I9sPlfW_V2e_Bc4CwVi7-aA=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="438" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEjvk-wlGS9SJdR0F0BdQybvyPQSb5WYHlQcXxXOJxc75txxCJpbpUfgIA4m-qZye6n-ImaEc18rZx0YSeJbTzP_meIXdbUQ8pIs4jrqB1HaNqVFPQcPrVuHD36gYqxNK3wUsSmHMB-q0RfXDYGgoQIAZeIHW406qG8gby7I9sPlfW_V2e_Bc4CwVi7-aA=s16000" /></a></div><div class="separator" style="clear: both; text-align: justify;">Now with all panels in place, clamps are re-positioned. The timber here allows less clamps to be used, applying the force over a larger area. Otherwise, more clamps with small spacings are required. <br /></div><div class="separator" style="clear: both; text-align: center;"> </div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEgEsx2ZsmpcJ4JgUEHeXmKGGmhsAYqDJ6Mtsz2_KH5ceqsIEK2ddS525TSk7a-aPI_pMfHnj4AoPd6ksq4etDNCsRsQ-bnoXTJGhul253f8h8-8dNrBo1ii0YXVc-9Dglbio0iKF0G7FkJb_9AD723tsWymrJ1r4C7v4AyDN4CcSiP6evMVOSE5jscpRw=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="482" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEgEsx2ZsmpcJ4JgUEHeXmKGGmhsAYqDJ6Mtsz2_KH5ceqsIEK2ddS525TSk7a-aPI_pMfHnj4AoPd6ksq4etDNCsRsQ-bnoXTJGhul253f8h8-8dNrBo1ii0YXVc-9Dglbio0iKF0G7FkJb_9AD723tsWymrJ1r4C7v4AyDN4CcSiP6evMVOSE5jscpRw=s16000" /></a></div><div class="separator" style="clear: both; text-align: justify;">This is the rear of the sub. A circular cut out allows the driver to be inserted into the internal baffle. The amp is then installed to a panel that goes over the top.<br /></div><div class="separator" style="clear: both; text-align: center;"><br /></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/a/AVvXsEiLn_I54DTgD6hap0A7TMKtqrv4j2DlzNAlOhpLtKpR8MrL_nGltZf4ekjqj9HT7dR_x_OwNpF5OCTp6DUvQCLvm1eiva6_y0JqP5HCD4kbFGvorG4nUZnR-FzZe96W9vcpPps7al8V3apgNFHnZh60jxlRYVsOP1cLyXc44O1TcjbB9U-PPlFcq2xmtQ=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="299" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEiLn_I54DTgD6hap0A7TMKtqrv4j2DlzNAlOhpLtKpR8MrL_nGltZf4ekjqj9HT7dR_x_OwNpF5OCTp6DUvQCLvm1eiva6_y0JqP5HCD4kbFGvorG4nUZnR-FzZe96W9vcpPps7al8V3apgNFHnZh60jxlRYVsOP1cLyXc44O1TcjbB9U-PPlFcq2xmtQ=s16000" /></a></div><p style="text-align: left;"></p>
<p style="text-align: justify;">The enclosure is left over night, then the next day, sanded and a small roundover is applied to all the joints.<br /></p><p style="text-align: left;"></p><p style="text-align: left;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEghYXTWD-gWsSib8g3VRhvtc8ePlBN0zb8mPSLMRl7pnBw61TmERTpYuGlvaVPKVr0-wTARu2WMQOJ6d7vefUHLC6psGns3ZTrOhFRKlapy8HwgT0YkMMQ0h2IYsv-Y87ialLDRwOHdOLzidq5N394IeRKK5xwaaetBB292ayV4CbK6rfF-kCpO4ZtIQA=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="476" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEghYXTWD-gWsSib8g3VRhvtc8ePlBN0zb8mPSLMRl7pnBw61TmERTpYuGlvaVPKVr0-wTARu2WMQOJ6d7vefUHLC6psGns3ZTrOhFRKlapy8HwgT0YkMMQ0h2IYsv-Y87ialLDRwOHdOLzidq5N394IeRKK5xwaaetBB292ayV4CbK6rfF-kCpO4ZtIQA=s16000" /></a></div><p style="text-align: left;"></p><p style="text-align: justify;">Next the driver can be installed. I like to insert string through the holes so the driver can be re-positioned. Otherwise the driver might not be rotated correctly and the pilot holes might not line up.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEgHQnBPnEsla4lOVB8nsJkpAhtiY3nMrQDmRZ4VA_Vi6bEbOi2ayd6Ult00iqcdbMtNxHs3vwp49YkHTWbGFunoz0cfrUcFxGe42mTQC-Igql0Mrk-Nvn-3HuNbx1XF-jsqXrKqqJZC45uHehvzc2D5LWIH8QsDgxTZNx7c0uJuHcAwXUuuRt6kAyOwnw=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="344" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEgHQnBPnEsla4lOVB8nsJkpAhtiY3nMrQDmRZ4VA_Vi6bEbOi2ayd6Ult00iqcdbMtNxHs3vwp49YkHTWbGFunoz0cfrUcFxGe42mTQC-Igql0Mrk-Nvn-3HuNbx1XF-jsqXrKqqJZC45uHehvzc2D5LWIH8QsDgxTZNx7c0uJuHcAwXUuuRt6kAyOwnw=s16000" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEg_GOxEFMXJg2ji4Hl3wynZUmRvtEkD_NZN6Ipfq374Jqz-CIaABdtTZGkdy39qxijpJ4ODXXbjhFbS0E9K2i2Xs64CBBc6IE5yjZ4P4K_wZPFUsXj7ADy06nzDp4sSyCtBVnCytfzS3TgTOUzwPOBzUcNRfkFUorXpL11BlE7Ot7RvoPOPOIoLjo8esQ=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="356" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEg_GOxEFMXJg2ji4Hl3wynZUmRvtEkD_NZN6Ipfq374Jqz-CIaABdtTZGkdy39qxijpJ4ODXXbjhFbS0E9K2i2Xs64CBBc6IE5yjZ4P4K_wZPFUsXj7ADy06nzDp4sSyCtBVnCytfzS3TgTOUzwPOBzUcNRfkFUorXpL11BlE7Ot7RvoPOPOIoLjo8esQ=s16000" /></a></div><p style="text-align: left;"></p><p style="text-align: justify;">The driver is lowered into the internal baffle. Cables are routed to avoid hitting the cone. Foam gasket avoids air leaks.<br /></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEiT2RQoTMea71bJIH1ecWgHHBWD8On5EkA2uSetkMvl8tHr0yH5Nb8Xe2myQuAO83k-02LAaCh8xba24-dl8ZRScrxPc35_uzD_ghH0GCibEtBwwJmBagCWaJSzPPldxCbQMTVnmWCtPbSTZywxRok8CDcDzDF_rMuaEq8pr4pzWOaGR_DGdM4qKq3dog=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="327" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEiT2RQoTMea71bJIH1ecWgHHBWD8On5EkA2uSetkMvl8tHr0yH5Nb8Xe2myQuAO83k-02LAaCh8xba24-dl8ZRScrxPc35_uzD_ghH0GCibEtBwwJmBagCWaJSzPPldxCbQMTVnmWCtPbSTZywxRok8CDcDzDF_rMuaEq8pr4pzWOaGR_DGdM4qKq3dog=s16000" /></a></div><p style="text-align: left;"></p><p style="text-align: justify;">Next the back panel is added and the sub is tested.<br /></p><p style="text-align: left;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEgSnLpQ7-V8VWU-h2IWYp6dO0YqUww67zsfzF-2hFaAtfc8oCrnQol79LWWCSayg4wb9OBs900Gs7eoEyRlFevE8rVsWnCrrqv6oLPU-HvOk7feJZh8tP0YSKsxN8JkNwdkICG2dy04oOTxoTGIg06tep2M8ncMudky_LwuUnQLd_QgW4wvRQFa2_BsBQ=s592" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="592" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEgSnLpQ7-V8VWU-h2IWYp6dO0YqUww67zsfzF-2hFaAtfc8oCrnQol79LWWCSayg4wb9OBs900Gs7eoEyRlFevE8rVsWnCrrqv6oLPU-HvOk7feJZh8tP0YSKsxN8JkNwdkICG2dy04oOTxoTGIg06tep2M8ncMudky_LwuUnQLd_QgW4wvRQFa2_BsBQ=s16000" /></a></div><br /></div><div style="text-align: justify;">It's not pretty, however, this sub is now located behind a large couch and can't be seen in the room. <br /></div><div><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /></div>Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com0tag:blogger.com,1999:blog-8689487740107692135.post-10251152209510279712022-01-04T01:59:00.007-08:002022-01-05T14:57:39.747-08:00Lil thumper<div style="text-align: justify;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjt2tgyq5tSKVj8EGVn0yY1MfZtSeeGPdNjNOjjSIGgU_0N6Cl9jKhCi5PFV_XvMBuQUDvJ7bGaoc_c5lMCncceOAIChAqf9cmRp3HvpX2fRJ0_-T2ZM-W2HGo-PqpvH7o1SXO-EnhRlwVQmlwcTwIKBi4XK1Aj_2rqY9PfiFD6_1VM2JNKD6DcseRUjw=s592" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="592" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEjt2tgyq5tSKVj8EGVn0yY1MfZtSeeGPdNjNOjjSIGgU_0N6Cl9jKhCi5PFV_XvMBuQUDvJ7bGaoc_c5lMCncceOAIChAqf9cmRp3HvpX2fRJ0_-T2ZM-W2HGo-PqpvH7o1SXO-EnhRlwVQmlwcTwIKBi4XK1Aj_2rqY9PfiFD6_1VM2JNKD6DcseRUjw=s16000" /></a></div><br /> </div><div style="text-align: justify;">Previously I referred to this compact bandpass sub, originally proposed for a client requesting a bandpass sub. However, I quickly realised it was ideal for another client seeking a quality compact sub for a lounge room system. This sub would be hidden behind a couch - I had already tested all viable positions in this room and determined that this particular location was ideal. </div><div style="text-align: justify;"> </div><h3 style="text-align: left;"> A classic driver </h3><p style="text-align: left;">This sub is built around a variant of the classic Peerless XLS series of sub drivers. </p><p style="text-align: left;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjCYJao7pOKE4mC-r_FXwrnwKYe8DvsaeR-FsFZ4CiM5G0N8lc2TFXVtI7O20mqPP00MhuxUsav30h_z75BpDBcwU68APaDK3e1N6KGxtkAQU7f08IMxch55tmdX_6K0ETuH2IxNE0uP4qYuhjazuc80VPR9QRwWfVRh8NJsP5vdhtyTRH44f6t_V1C7A=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="344" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEjCYJao7pOKE4mC-r_FXwrnwKYe8DvsaeR-FsFZ4CiM5G0N8lc2TFXVtI7O20mqPP00MhuxUsav30h_z75BpDBcwU68APaDK3e1N6KGxtkAQU7f08IMxch55tmdX_6K0ETuH2IxNE0uP4qYuhjazuc80VPR9QRwWfVRh8NJsP5vdhtyTRH44f6t_V1C7A=s16000" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEhB5bn8UGl0ho1WVuRzoC59ulRyXt8MjtduNEiU7DA70OnjI9qoPFzI0VqyEH4zd_8MRiTT_8N1uR0WwrUh3hjn4azgekgG7bvd3jcdzkfF7lVkDO4ORwdVph_JYs09V6qy2HlX35qEL9qip7_sfwYALPTLmA1uZ6eI6q1TxRhCN9ipP69wUTjbR7b6dA=s550" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="356" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEhB5bn8UGl0ho1WVuRzoC59ulRyXt8MjtduNEiU7DA70OnjI9qoPFzI0VqyEH4zd_8MRiTT_8N1uR0WwrUh3hjn4azgekgG7bvd3jcdzkfF7lVkDO4ORwdVph_JYs09V6qy2HlX35qEL9qip7_sfwYALPTLmA1uZ6eI6q1TxRhCN9ipP69wUTjbR7b6dA=s16000" /></a></div><br /> <p></p><p style="text-align: left;">Given the vast array of drivers now available, the classic drivers are often overlooked. However, this project serves as a reminder of that clean and articulate bass that made this series of drivers legendary. The particular variant I'm using here is the Scan Speak version - 30W/4558T00.
As with all Scan Speak drivers, we see excellent build quality, including a die cast aluminium frame which is well ventilated along with an aluminium shorting ring to lower inductance. Unlike more typical modern drivers, the surround is quite large relative to the linear excursion capabilities of the driver. Hence at xmax, this driver is not in any way pushing the limits of the suspension system. The modest 51mm diameter voice coil along with the shorting ring means a very low inductance value of 0.83 mH. </p><h3 style="text-align: left;"> 4th vs 6th order bandpass </h3><p style="text-align: left;">A 4th order bandpass, such as we are using here, offers a few advantages. Firstly, the sealed rear chamber provides inbuilt excursion protection. Even if we aren't using a rumble filter, the driver is protected from extreme excursions by the sealed air spring in the enclosure. 6th order and ported designs don't offer this protection and this means they require a high pass (rumble) filter that is not adequate on many plate amps and which is not available on AV receivers. This usually means we need to add an external DSP device. In this case, a 4th order design meant we could simply use the DSP filters built into the AVR. The enclosure is also smaller than a 6th order design. </p><h3 style="text-align: left;">How does it sound? </h3><p style="text-align: left;">Exactly as expected with this driver, the bass is clean and articulate. True to its name, the bass is punchy due to its tuning. As this is a fairly casual system, mainly used for music and Netflix, this client wasn't aiming for the kind of LFE extension home theatre enthusists normally choose. From the very first test sweep it was clear that this would be a trouble free sub. </p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEgJhha1W2OUImmmlq1RB7VxoGO3xLTsOIiWxd6ws__9oCIt0TIolWQgbT8dPU6j-ncGhsJLOqb8CeriDPEouPHzV40yXHu8gEHmlS33mra7sFy28749val14K0Pe_yHEcwbipfPs_sZtPjpDUTrg-F_xT8plSNCvp5T9FV_NU7dGC_elYbaTUZfBi1NfA=s559" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="559" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEgJhha1W2OUImmmlq1RB7VxoGO3xLTsOIiWxd6ws__9oCIt0TIolWQgbT8dPU6j-ncGhsJLOqb8CeriDPEouPHzV40yXHu8gEHmlS33mra7sFy28749val14K0Pe_yHEcwbipfPs_sZtPjpDUTrg-F_xT8plSNCvp5T9FV_NU7dGC_elYbaTUZfBi1NfA=s16000" /></a></div><p style="text-align: left;"> </p><p style="text-align: left;">Shown here is the nearfield response. You can see the port resonance at 520 Hz. The chamber is lined with 50mm thick high density acoustic material, which is very effective at damping port resonances. This is no the lining that you normally see in speakers and subs. It's extra high density Martini Absorb XHD, as used in bass traps. The lining typically used in speaker boxes is often not adequate for a bandpass design. </p><p style="text-align: left;"></p><h3 style="text-align: left;">Cabinet design</h3><p style="text-align: left;">The driver is surface mounted onto a double thickness internal baffle (36mm thick) and secured with T nuts and cap screws. The driver faces a sealed chamber adjacent to the 200W plate amp. This provides excursion protection. The driver magnet faces the front chamber, which has a rectangular port. The internal baffle is heavily braced on both sides and the result is a very inert cabinet.<br /> </p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEilVpwQCdo_dHBnehjs0KFFD6YjQSLxAgJj_TASTCrCIC0eSkm2nL5hRWPa_3hZ8e3ewAiG5lyNgoGjKndHuECiCOoDJELlrdBPD0JxNLoy1rMoJfCzmwVmAxY9fIItWMSq-LLEJHZR1H977DksXXd8sI82-KYl0Jz_THtUI8z9OG3KUIlDOi_nWhNpVg=s612" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="612" data-original-width="529" src="https://blogger.googleusercontent.com/img/a/AVvXsEilVpwQCdo_dHBnehjs0KFFD6YjQSLxAgJj_TASTCrCIC0eSkm2nL5hRWPa_3hZ8e3ewAiG5lyNgoGjKndHuECiCOoDJELlrdBPD0JxNLoy1rMoJfCzmwVmAxY9fIItWMSq-LLEJHZR1H977DksXXd8sI82-KYl0Jz_THtUI8z9OG3KUIlDOi_nWhNpVg=s16000" /></a></div><p>In this design I've opted for a rectangular port. It performs better than a shelf port due to reducing the surface area. A shelf port extending all the way to the sides would have higher port compression. A round port limits the options for getting the right length. In this design, I needed precise control over the port area, so that I could get it to terminate at the internal baffle. With a round port, I'd have to accept big steps in sizes. With this design, it took some careful juggling to get both volumes optimised and to have the port match the depth of the rear sealed chamber. Round ports also introduce some challenges with flaring the inside and also with build sequence. </p><h3 style="text-align: left;">Flat pack<br /></h3><p>As with all our builds, a CNC machined flat pack is available.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEgcqVbtgevNcIKDvyEhulF7aMJgl02tHR0Cs7FieqL3ND_yv9imstb4CVjYR3pWv7Jxjb4CoL8y5UVIVbn-KMYVBQddHls0FlhkYwUe7q0MLtHA70JEHkgpSUxVveua0LGYEvUfaaUYZlvqdrhqZqxHzq27lcmjm4D1h5kTqT4EeZrWsl7VDNmEjza0vw=s550" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="265" data-original-width="550" src="https://blogger.googleusercontent.com/img/a/AVvXsEgcqVbtgevNcIKDvyEhulF7aMJgl02tHR0Cs7FieqL3ND_yv9imstb4CVjYR3pWv7Jxjb4CoL8y5UVIVbn-KMYVBQddHls0FlhkYwUe7q0MLtHA70JEHkgpSUxVveua0LGYEvUfaaUYZlvqdrhqZqxHzq27lcmjm4D1h5kTqT4EeZrWsl7VDNmEjza0vw=s16000" /></a></div><br /><p><br /></p>Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com0tag:blogger.com,1999:blog-8689487740107692135.post-56101603092232926292022-01-04T01:20:00.002-08:002022-01-04T01:20:26.118-08:00Big thumper - 6th order bandpass sub with Dayton Reference RSS315HO<p>Previously I introduced this design as a custom sub offered as an upgrade to a smaller bandpass sub they initially intended.
<b> </b></p><p><b>The driver: Dayton Audio Reference RSS315HO</b> </p><p>RSS315HO is a driver that works in many designs. It's a driver intended for car audio use, mainly due to its parameters which suit a small enclosure. Often the HO versions of the Dayton Reference series work well in horn designs but in this case, it also works well in a bandpass enclosure. What I like about the Dayton Reference series is that they are well optimised for sound quality, avoiding the temptation to go extreme in xmax and instead focusing on aspects that give us high quality bass when the design is right. </p><h3 style="text-align: left;"><b>Why bandpass?</b> </h3><p>The short answer is "because the client requested a custom bandpass sub." But why would someone choose bandpass over all the other options. In the past, bandpass subs have been unfairly associated with low quality subs. Often either really cheap computer mini subs or one note noise makers. Many audiophiles after decades in this hobby have not actually experienced a serious bandpass sub. In reality, bandpass designs offer some strong advantages with serious potential. However, let's cover the downsides first.
<b> </b></p><h3 style="text-align: left;"><b>Why to avoid bandpass</b> </h3><p>Bandpass subs are more difficult to design than sealed or ported designs. They are highly sensitive to misalignment. The final result can often be different to a computer model in ways that makes the final design perform poorly. Many programs are not sophisticated enough to accurately predict their real behaviour. So there is always a little more risk that the final result won't rise to the level of expectations. Further, we see higher group delay with bandpass designs, coupled with port resonances out of band that can seriously degrate the sound. Often typical speaker box lining won't effectively damp the resonances, leaving us with a sub that doesn't sound quite right. Hence, in a poorly excuted design we could see multiple compounding problems. <br /><br />In a well executed design we can achieve some compelling advantages, including: </p><ul style="text-align: left;"><li>higher sensitivity where we are willing to reduce bandwidth</li><li>reduced cone excursion for a given SPL level</li><li>lower distortion related to the above advantages</li><li>the front chamber further lowers distortion due to acoustic low pass filtering</li><li>greater maximum output and dynamics</li><li>the ability to drive a sub harder before distortion becomes objectionable</li></ul><h3 style="text-align: left;"><b> The cabinet and bracing design</b></h3><p>This cabinet has two main horizontal braces that also form part of the port walls. Shelf ports also form the internal walls of the ports, which wrap around the enclosure. Since all the output of a bandpass sub passes through the ports, their design is critical. Bandpass subs are typically more prone to audible port chuffing. Hence this design has very large ports with flares on both inlet and outlet of both ports. </p><p>Build photos coming ...<br /></p>Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com0tag:blogger.com,1999:blog-8689487740107692135.post-64399331032015348882022-01-04T00:00:00.001-08:002022-01-05T14:55:49.788-08:00A tale of two bandpass subs<p>Covid lockdown here in Australia has seen many people stuck at home with renewed focus on enjoying their listening rooms. During lockdown, one client approached us looking for a custom sub similar to one he had heard in the past and found impressive. He presented a fairly simple bandpass design, based around a budget 8" driver and a simple and easy to build cabinet. I could see how this design could work for people wanting an easy to build project but I had concerns about applying a bandpass design to other drivers. They tend to be very sensitive to swapping out drivers. I also felt, we could offer something far more impressive. So I presented two options. I'll call them "big thumper" and "little thumper." <br /><br />Big Thumper was a large 6th order bandpass with a 1kw amp and a Dayton 12" driver. Given this is a music sub with fairly generous allowed dimensions, I was able to maximise sensitivity and achieve 91 dB voltage sensitivity. Lil thumper was a more modest animal, using an old favourite driver - a variant of the Peerless XLS range paired with a 200W amp. This was a smaller and simpler design - 4th order bandpass. That means effectively a sealed box sub with a front chamber attached. This bumps up the sensitivity and filters the distortion. Normally a sealed design would achieve 86 dB at 40 Hz (2.83V) but here with a bandpass design we can get it up to 92 dB.<br /><br />This client chose to go ahead with the larger design but then another client chose to go ahead with lil thumper. <br /><br /><a href="http://redspade-audio.blogspot.com/2022/01/lil-thumper.html">Lil Thumper - a compact 4th order bandpass sub ></a></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercohttp://redspade-audio.blogspot.com/2022/01/lil-thumper.html" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="592" data-original-width="550" height="320" src="https://blogger.googleusercontent.com/img/a/AVvXsEjt2tgyq5tSKVj8EGVn0yY1MfZtSeeGPdNjNOjjSIGgU_0N6Cl9jKhCi5PFV_XvMBuQUDvJ7bGaoc_c5lMCncceOAIChAqf9cmRp3HvpX2fRJ0_-T2ZM-W2HGo-PqpvH7o1SXO-EnhRlwVQmlwcTwIKBi4XK1Aj_2rqY9PfiFD6_1VM2JNKD6DcseRUjw=s320" width="297" /></a></div><br /> <p></p><p><br /></p>Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com0tag:blogger.com,1999:blog-8689487740107692135.post-51249385551688047232020-09-15T19:20:00.004-07:002020-09-15T19:22:25.214-07:00The surprising reason why you might need a sub in your studio<p style="text-align: justify;"><span style="font-family: arial;">This is an issue that comes up often in a studio consult session. Usually my services are engaged to give advice on acoustic treatment for a studio. The first thing I will do after an initial discussion is test how the monitors are performing in the mix position. This is where it's quite common to find a problem that looks like this:</span></p><p style="text-align: justify;"><span style="font-family: arial;"><br /></span></p><div style="text-align: justify;"><span style="font-family: arial;"><br /></span></div><div class="separator" style="clear: both; text-align: justify;"><a href="https://1.bp.blogspot.com/-c7M_MdTWbH4/X2FwN83MedI/AAAAAAAAEnk/jlMpgM6oFA4rdok-_ihkED0pC7aCwUWzgCLcBGAsYHQ/s550/Monitors%2Bin%2Bmix%2Bposition.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="268" data-original-width="550" src="https://1.bp.blogspot.com/-c7M_MdTWbH4/X2FwN83MedI/AAAAAAAAEnk/jlMpgM6oFA4rdok-_ihkED0pC7aCwUWzgCLcBGAsYHQ/s16000/Monitors%2Bin%2Bmix%2Bposition.jpg" /> </a><span style="font-family: arial;"></span></div><div class="separator" style="clear: both; text-align: justify;"><span style="font-family: arial;"> </span></div><div class="separator" style="clear: both; text-align: justify;"><span style="font-family: arial;">The mic was placed in the mix position to show how the monitors measure in the room, as they will be used. Clearly there is no bass response. In general this is not necessarily a good reason to add a sub. Decent quality monitors are not necessarily very expensive and it's not hard to find monitors with adequate extension for most music. </span></div><div class="separator" style="clear: both; text-align: justify;"><span style="font-family: arial;"><br /></span></div><div class="separator" style="clear: both; text-align: justify;"><span style="font-family: arial;">In this case, the monitors themselves were a limiting factor. We brought in a 12" sealed woofer to test the bass response. This woofer had already been calibrated for a flat anechoic response with plenty of bass extension. Here is the nearfield measurement:</span></div><div class="separator" style="clear: both; text-align: justify;"><span style="font-family: arial;"> </span></div><div class="separator" style="clear: both; text-align: justify;"><span style="font-family: arial;"> </span><div class="separator" style="clear: both;"><a href="https://1.bp.blogspot.com/-hJTXN0CJLSk/X2Fxm9TXB0I/AAAAAAAAEoI/l4Mbt2OKL2obk2pNBsi8Z-qjjWyV67AbACLcBGAsYHQ/s550/NF%2Bsealed%2B12in%2Bwoofer.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="268" data-original-width="550" src="https://1.bp.blogspot.com/-hJTXN0CJLSk/X2Fxm9TXB0I/AAAAAAAAEoI/l4Mbt2OKL2obk2pNBsi8Z-qjjWyV67AbACLcBGAsYHQ/s16000/NF%2Bsealed%2B12in%2Bwoofer.jpg" /></a><span style="font-family: arial;"></span></div><div class="separator" style="clear: both;"><span style="font-family: arial;"> </span></div><div class="separator" style="clear: both;"><span style="font-family: arial;">Next we tested in the mix position, with comparison to the existing monitors:<br /></span></div></div><div class="separator" style="clear: both; text-align: justify;"><span style="font-family: arial;"><br /></span></div><div class="separator" style="clear: both; text-align: justify;"><a href="https://1.bp.blogspot.com/-nZNXV578_J8/X2FxnNqoEPI/AAAAAAAAEoM/G5FnXVbEVmQPkcIcp2dNZbTZ2YsLQwwHgCLcBGAsYHQ/s550/Existing%2Bmonitors%2Bvs%2B12in%2Bsealed%2Bwoofer.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="299" data-original-width="550" src="https://1.bp.blogspot.com/-nZNXV578_J8/X2FxnNqoEPI/AAAAAAAAEoM/G5FnXVbEVmQPkcIcp2dNZbTZ2YsLQwwHgCLcBGAsYHQ/s16000/Existing%2Bmonitors%2Bvs%2B12in%2Bsealed%2Bwoofer.jpg" /></a><span style="font-family: arial;"></span></div><p style="text-align: justify;"><span style="font-family: arial;">We see a similar response without the early roll off. Clearly there is a room related dip of around 17 dB. This is far too much to resolve with EQ due to the headroom required. We need an acoustic solution. </span></p><p style="text-align: justify;"></p><p style="text-align: justify;"><span style="font-family: arial;">The first solution is to optimise the position of the monitors and the mix position. This tends to offer limited improvement and normally we don't effectively resolve a dip related to room modes in this way. We can reduce the depth of a null with bass traps but typically this won't remove a null this deep. In situations like this, the most effective solution is usually a sub in an optimised location.<br /><br /></span></p><div class="separator" style="clear: both; text-align: justify;"><a href="https://1.bp.blogspot.com/-GE-eqyN-ZI0/X2Fxm0szL8I/AAAAAAAAEoE/HNnlUdvulbUjksqQsFSsnXdo8ji-YQnIwCLcBGAsYHQ/s550/Optimised%2Bsub%2Bposition.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="320" data-original-width="550" src="https://1.bp.blogspot.com/-GE-eqyN-ZI0/X2Fxm0szL8I/AAAAAAAAEoE/HNnlUdvulbUjksqQsFSsnXdo8ji-YQnIwCLcBGAsYHQ/s16000/Optimised%2Bsub%2Bposition.jpg" /></a><span style="font-family: arial;"></span></div><div class="separator" style="clear: both; text-align: justify;"><span style="font-family: arial;"> </span></div><div class="separator" style="clear: both; text-align: justify;"><span style="font-family: arial;">We used the same woofer to test every feasible sub position in the room. One of the better positions is shown here. You can see that a sub with a little EQ removes the problem entirely. Just a little EQ is required to shape the response into a flat overall trend. </span></div><div class="separator" style="clear: both; text-align: justify;"><span style="font-family: arial;"><br /></span></div><div class="separator" style="clear: both; text-align: justify;"><h3><span style="font-family: arial;">One way to know</span></h3></div><div class="separator" style="clear: both; text-align: justify;"><span style="font-family: arial;"> </span></div><div class="separator" style="clear: both; text-align: justify;"><span style="font-family: arial;">Not every studio needs a sub. The most important factor is how your monitors measure in your particular room. If your monitors have adequate extension and headroom and a reasonably flat response in your mix position, there is no great need to add a sub. It's a solution that I recommend only where it's required. When it comes to buying a sub, many studio owners have a tendency to first try a cheap sub. Whilst it's true that you can actually get decent monitors for a modest price, the same is not true with subs. Generally speaking, most subs below AUD $1500 are not up to the task. This is why I advise people to have the room tested and implement a sub only where it's needed. <br /></span></div><div class="separator" style="clear: both; text-align: justify;"><span style="font-family: arial;"><br /></span></div><div style="text-align: justify;"><span style="font-family: arial;"><br /></span></div><div class="separator" style="clear: both; text-align: justify;"><span style="font-family: arial;"><br /></span></div><div class="separator" style="clear: both; text-align: justify;"><span style="font-family: arial;"> </span></div><div class="separator" style="clear: both; text-align: justify;"><span style="font-family: arial;"> <br /></span></div><div style="text-align: justify;"><span style="font-family: arial;"><br /></span></div><p style="text-align: justify;"><span style="font-family: arial;"><br /></span></p>Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com0tag:blogger.com,1999:blog-8689487740107692135.post-75346946909295478092020-05-18T18:18:00.002-07:002020-05-18T18:18:53.202-07:00Why you don't need two subs<div dir="ltr" style="text-align: left;" trbidi="on">
By now you've heard it said many times "two subs are better than one." So it might come as a surprise to hear it's not always the case. Quite often it's the wrong advice. The answer is not quite as simple as the one most audiophiles seek. People like simple ideas that make intuitive sense. This is why myths in audio are so prevalent - they are simple ideas that seem to make intuitive sense, so they spread on forums. When something makes sense, people are reluctant to change their minds. My aim with this post is to arm you with the information to help you make a better choice for your particular situation.<br />
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The case for more than one subwoofer</h3>
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There are only two technical reasons for more than one sub:<br />
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1. Output - you want more clean output than a single sub can provide<br />
2. Smooth response - no single sub position can provide a smooth response in the seats that matter<br />
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There are many non-technical reasons, but I'm going to stick with what provides an audible benefit for your dollar.<br />
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If your goal is to increase output, it's worth keeping in mind that two subs can work against each other. Here is an example:<br />
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<a href="https://1.bp.blogspot.com/-iTSJg9G4lHY/XsMranylQRI/AAAAAAAAEhA/GgQnE3CDffomKj4Rt9P1V3mNFKFZZqhGQCLcBGAsYHQ/s1600/2subs550.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="241" data-original-width="550" src="https://1.bp.blogspot.com/-iTSJg9G4lHY/XsMranylQRI/AAAAAAAAEhA/GgQnE3CDffomKj4Rt9P1V3mNFKFZZqhGQCLcBGAsYHQ/s1600/2subs550.jpg" /></a></div>
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These two sealed subs have a different response due to their positions. How do they sum when measured together?<br />
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<a href="https://1.bp.blogspot.com/-Iz-FIVYKESY/XsMratyAu2I/AAAAAAAAEhE/60bb3G4NWsItMJr325f59QobCm_WyM-SACPcBGAYYCw/s1600/2subs-combined550.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="241" data-original-width="550" src="https://1.bp.blogspot.com/-Iz-FIVYKESY/XsMratyAu2I/AAAAAAAAEhE/60bb3G4NWsItMJr325f59QobCm_WyM-SACPcBGAYYCw/s1600/2subs-combined550.jpg" /></a></div>
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Here you can see that in the low bass range, below 43 Hz they actually provide a less smooth response and lower output than just a single sub in the blue position!<br />
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This is where things work against those who buy subs, put them in the room and hope for the best. The point to take away here is that the benefit is not automatic. You can't simply put multiple subs into a room and get the benefit so many are talking about.<br />
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So you might be wondering when I'm going to present the case for more than one. Here it is. There are many rooms where one sub isn't enough. Here is a good example of a room that requires two.<br />
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This was a fairly typical dedicated rectangular room, with one row of seating in a good sized room. This client came to use looking for the missing midbass punch. The interesting thing here was that they didn't put it quite that way. They initially believed that they were missing bass depth. They had one sub up the front of the room:<br />
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<a href="https://1.bp.blogspot.com/-H1QNbBXumxY/XsMtnQgrjjI/AAAAAAAAEhU/sedQJQsw14AK81lbfDT4zqySkQNOdr6MwCLcBGAsYHQ/s1600/2sub-eg-existing.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="241" data-original-width="550" src="https://1.bp.blogspot.com/-H1QNbBXumxY/XsMtnQgrjjI/AAAAAAAAEhU/sedQJQsw14AK81lbfDT4zqySkQNOdr6MwCLcBGAsYHQ/s1600/2sub-eg-existing.jpg" /></a></div>
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The large peak around 26 Hz is provided by the room and it allowed a small sealed sub to punch beyond its weight. It achieved good output to near 20 Hz. But the real problem was in the midbass. There is a large recess around 30 - 45 Hz. In movies a great deal of the action lies in this range. I'd argue this region is more important than 20 - 30 Hz. We tested every possible position in this room. No single position could provide a smooth response. Hence we changed our focus to finding two positions that would work well together.<br />
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Along the front of the room, we found a better position:<br />
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<a href="https://1.bp.blogspot.com/-kgR4eQt-6qA/XsMtn1ZpZ6I/AAAAAAAAEhk/03Q_rO2SSkovL8QJ9jUFqox3GjhqHc7AACPcBGAYYCw/s1600/2sub-eg-existing-vs-frc.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="241" data-original-width="550" src="https://1.bp.blogspot.com/-kgR4eQt-6qA/XsMtn1ZpZ6I/AAAAAAAAEhk/03Q_rO2SSkovL8QJ9jUFqox3GjhqHc7AACPcBGAYYCw/s1600/2sub-eg-existing-vs-frc.jpg" /></a></div>
Moving this sub, we removed a dip to achieve smoother upper bass. Then we found a position for a second sub that just happened to be under an existing coffee table that was large enough to hide a sub.<br />
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<a href="https://1.bp.blogspot.com/-cNXaA15sNAQ/XsMtnpbv62I/AAAAAAAAEho/Cb5o0eKKZzYGjiBSqyofZh_5xzR8ozQpwCPcBGAYYCw/s1600/2sub-eg-2best.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="241" data-original-width="550" src="https://1.bp.blogspot.com/-cNXaA15sNAQ/XsMtnpbv62I/AAAAAAAAEho/Cb5o0eKKZzYGjiBSqyofZh_5xzR8ozQpwCPcBGAYYCw/s1600/2sub-eg-2best.jpg" /></a></div>
The second position solves the midbass punch issue. With these two positions, we now have a chance to fix the bass.<br />
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The final result was a dramatic increase in bass authority and dynamics. Movies delivered a more visceral experience that was lacking before.<br />
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The case for just one subwoofer</h3>
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For audiophiles who just want the best bass in one listening chair, I've found that about half of the rooms we test need one sub and the other half are better served with two. Here is an example of one room that suits just one sub. All the positions we tested:<br />
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<a href="https://1.bp.blogspot.com/-w3bTtL90Uwc/XsMxh6BltgI/AAAAAAAAEhw/Xhsy9ms5et4HLw07_vZ6oLYvKS9DPvCmQCLcBGAsYHQ/s1600/1sub-eg-all.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="237" data-original-width="550" src="https://1.bp.blogspot.com/-w3bTtL90Uwc/XsMxh6BltgI/AAAAAAAAEhw/Xhsy9ms5et4HLw07_vZ6oLYvKS9DPvCmQCLcBGAsYHQ/s1600/1sub-eg-all.jpg" /> </a></div>
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As you can see, the positions vary enormously. Here are a few positions that are interesting:</div>
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<a href="https://1.bp.blogspot.com/-NcuuLVoQmKI/XsMxiZSvd4I/AAAAAAAAEh0/JU51nr-V8JcwrW1pbA9eVa1xy51tirMXACPcBGAYYCw/s1600/1sub-eg-3.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="237" data-original-width="550" src="https://1.bp.blogspot.com/-NcuuLVoQmKI/XsMxiZSvd4I/AAAAAAAAEh0/JU51nr-V8JcwrW1pbA9eVa1xy51tirMXACPcBGAYYCw/s1600/1sub-eg-3.jpg" /></a></div>
This client had many subs in the room, most of them in positions that aren't effective. One of them was in the blue position, which performs very well for 2 channel. The orange position is one of the worst. I've shown it here to give an idea of how badly the room can impact the response. The black position is similar to one that he was using, but you can see it provides a lot more free output. In this room, only one sub is required with moderate EQ.<br />
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This room is one of the best I've seen for using just one sub. Yet surprisingly, they had many subs running in the room. The message here is clear - <b>always test the room before you decide how many subs you need.</b><br />
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It's surprisingly common for people who just need one sub to have several. If your plan is to buy a sub then hope for the best, I always recommend just one sub. Where you want to take the next step, my advice is always the same. Test the room. This means either learning how to do it, or engaging a service like ours to do it for you. </div>
Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com1tag:blogger.com,1999:blog-8689487740107692135.post-80584348065644243522017-06-21T03:35:00.003-07:002017-06-21T03:35:44.056-07:00Rythmik 12" flat pack<div dir="ltr" style="text-align: left;" trbidi="on">
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We now have a standard flat pack for the Rythmik 300W kit:</div>
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This is designed for the 300W Hypex amp version, which has a slightly larger enclosure than F12. The height is increased to gain extra volume. </div>
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Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com0tag:blogger.com,1999:blog-8689487740107692135.post-14734398862788237632017-06-21T00:34:00.000-07:002017-06-21T00:34:09.947-07:00Rythmik custom curved sub prototype<div dir="ltr" style="text-align: left;" trbidi="on">
We're offering this prototype build for sale. Contact us to express interest.<br />
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CAD diagrams show the design details which might not be as clear in the photos. <br />
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Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com0tag:blogger.com,1999:blog-8689487740107692135.post-71302674027020719622017-06-17T20:04:00.001-07:002017-06-17T20:18:23.547-07:00JV60 crossover upgrades<div dir="ltr" style="text-align: left;" trbidi="on">
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It's not unusual for us to receive numerous emails each week asking if we still offer upgraded crossovers for JV60. This is one that we built yesterday:</div>
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These are hand made with quality parts and the
modifications I used as a JV60 owner. The mods were make or break in my case,
resulting in keeping my JV60 speakers for many years. I actually found the sound
to be more enjoyable than many high end speakers, priced well above $10k. The sound is smoother and more refined.<br />
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Crossover upgrades</h3>
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We actually offer crossover upgrades for any speaker. This includes:<br />
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<li>Hand built crossovers using the same design but upgraded parts</li>
<li>Design mods to adjust the sound to your preferences</li>
<li>Modified designs to suit new drivers</li>
<li>Custom crossovers for custom speakers</li>
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Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com0tag:blogger.com,1999:blog-8689487740107692135.post-11391780514010065002017-06-13T04:28:00.002-07:002017-06-13T04:39:35.171-07:00Emerald Rock Studio<div dir="ltr" style="text-align: left;" trbidi="on">
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In most cases, our services are engaged after a client has already purchased acoustic treatment. Very often we are called in when there is a specific and objectionable problem they were not able to solve with generic and free advice on the internet. Here we started working with the client before the studio was built and so this meant we could ensure a great result right from the start.</div>
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Bass traps</h3>
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Most bass traps on the market are best described as "low midrange" absorbers. Their effectiveness is typically very limited. Here we built custom bass traps, running floor to ceiling. The traps are 340mm deep and 1000mm wide. One in each corner.</div>
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The bass traps are resistive and operate deliberately into the mid and treble regions. The advantage here is that they serve a dual function and actually reduce the amount of midrange absorbers that would otherwise be required. The traps were built as 8 modules, which were then bolted together once delivered onsite. A further advantage of the large depth is that they are more stable. These traps were made with Polymax XHD which we also sell as raw panels for DIYers. </div>
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Vicoustic Wavewood panels are mounted either side of the rear corner bass traps. This space is also a band practise space. It was important to create a neutral sounding room which was not overly dead. Part of creating this balance was mixing diffusion and absorption. </div>
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Vicoustic Multifusors are installed on the ceiling. These are very cost-effective panels and we like how easy they are to install. Being a light weight polystyrene panel, they can be installed with self adhesive picture hanging strips. It's an easy DIY install, which avoids the extra cost of a professional install job. </div>
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It was actually this product that first prompted us to become a Vicoustic dealer - it was clear that many of our clients needed an easy to install low cost diffusor.</div>
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<a href="https://1.bp.blogspot.com/-pp4i7VTwo34/WT_FVxC5VHI/AAAAAAAAEK8/Vg6rYQMkbtQp--TU6JIUCJGJZIwF9eN9wCLcB/s1600/IMG_3493.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="756" data-original-width="550" src="https://1.bp.blogspot.com/-pp4i7VTwo34/WT_FVxC5VHI/AAAAAAAAEK8/Vg6rYQMkbtQp--TU6JIUCJGJZIwF9eN9wCLcB/s1600/IMG_3493.jpg" /></a></div>
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SVS SB1000 subwoofer set up under the mixing desk. We consider this sub to be a value leader. It's a capable sub with very good performance for the price of a raw driver and amp. Many studios install a cheapie sub and most of them are simply not worth using. The temptation is often there to buy a sub in the $500 - 700 price range. These can only be considered "junk subs." It's a very good idea to spend just a little more for a sub that is far superior. We provided the sub along with calibration. We tested every feasible sub location, finally opting for the most practical placement with the best performance. Here a nearfield location worked best. </div>
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<a href="https://2.bp.blogspot.com/-RwzX69nJQhE/WT_FWUqY3iI/AAAAAAAAELA/YcvTRBcfaScP_PO2i_Bl7R_OsMm2nq1iACLcB/s1600/IMG_3494.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="367" data-original-width="550" src="https://2.bp.blogspot.com/-RwzX69nJQhE/WT_FWUqY3iI/AAAAAAAAELA/YcvTRBcfaScP_PO2i_Bl7R_OsMm2nq1iACLcB/s1600/IMG_3494.jpg" /></a></div>
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Very often the placement of the monitors and their relationship with their surrounds can create issues. A very accurate monitor is easily undermined with poor setup and a hit and miss approach. We worked through various options with placement to determine the optimal setup. </div>
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<a href="https://2.bp.blogspot.com/-R0_3515bOP0/WT_FWm9hxiI/AAAAAAAAELI/KBWkru0xC7QCHjgALzkkFgYmX-hrZ1PVQCLcB/s1600/IMG_3511.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="390" data-original-width="550" src="https://2.bp.blogspot.com/-R0_3515bOP0/WT_FWm9hxiI/AAAAAAAAELI/KBWkru0xC7QCHjgALzkkFgYmX-hrZ1PVQCLcB/s1600/IMG_3511.jpg" /></a></div>
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Products and services included here:</div>
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<li>Consultation on design and layout of the space prior to construction</li>
<li>Acoustic treatment design</li>
<li>Custom acoustic treatment</li>
<li>SVS sub</li>
<li>Sub integration </li>
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Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com0tag:blogger.com,1999:blog-8689487740107692135.post-27152798948484076662017-06-04T19:23:00.000-07:002017-06-04T19:57:37.045-07:00Point source mini - realising a compact point source speaker<div dir="ltr" style="text-align: left;" trbidi="on">
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This is a speaker we've wanted to create for some time. Perhaps our most versatile ever. We wanted to create a compact point source speaker. It would cater to some unique situations:</div>
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<li>nearfield monitors</li>
<li>a small room where a deeply involving sound stage is desired</li>
<li>valve and lower powered amplifiers</li>
<li>a centre channel speaker that can be placed on its side</li>
<li>a surround speaker with equal horizontal and vertical dispersion to serve more than one row of seats </li>
<li>a premium Atmos ceiling surround speaker (which doesn't measure so badly the response plot has to be hidden) </li>
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These are quite diverse situations but all of them benefit greatly from a point source speaker. We decided to commence working on this project and the first step was finding the right driver.</div>
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One promising driver was the Eminence Beta8CX. The parameters were quite useful and initially it seemed quite appealing that any compression driver with a thread could be tested. We're quite fussy on which compression driver we use as they are very often make or break with HE designs. Price was also an attractive feature. We know that people don't tend to spend big on surround speakers, so this was a key issue.</div>
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The Eminence driver has useful sensitivity and works well in a reasonably compact enclosure. However, when we tested various compression drivers, we noticed a serious problem.</div>
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There is a broad 15 dB valley from 4 - 11k. We tried various compression drivers but all exhibited a similar problem. Even with the benefit of a DSP active crossover, the sonic result was poor. One of our requirements was the ability to use a passive crossover, where we don't have the option to simply add EQ to a valley this large.</div>
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A further challenge with coaxial drivers is that they tend to be expensive. Money does not necessarily buy you exceptional performance. The reality is the coaxial drivers are difficult to get right.</div>
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Here is an example of one of the better units:</div>
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<a href="https://2.bp.blogspot.com/-U0dBnI_wzdg/WTS4NYLpVJI/AAAAAAAAEKM/BMF_unhaaDsY5ATjviYFPfVwSRhLw1TRQCLcB/s1600/Good-pro-coax.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="292" data-original-width="550" src="https://2.bp.blogspot.com/-U0dBnI_wzdg/WTS4NYLpVJI/AAAAAAAAEKM/BMF_unhaaDsY5ATjviYFPfVwSRhLw1TRQCLcB/s1600/Good-pro-coax.png" /></a></div>
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This woofer is mounted in a different enclosure so it's not directly comparable in all respects, however, the far superior response in the treble region is clear. Despite being one of the best, we can still see some obvious problems. Numerous dips in the woofer response above 1k where we are likely to want to cross to the tweeter. A peak just above 4k which is very audible. We can also see that the compression driver has very limited bottom end response.</div>
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The Game changer</h3>
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Here we have a driver that changes the game. Without this driver, this project would not get off the ground.</div>
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<a href="https://4.bp.blogspot.com/-HTSOTN9-sx0/WTSz1uwDA4I/AAAAAAAAEJ4/ETASbFtem4cpeadl15peCijmF1gsTSZkwCEw/s1600/AV8C-driver-front.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="556" data-original-width="550" src="https://4.bp.blogspot.com/-HTSOTN9-sx0/WTSz1uwDA4I/AAAAAAAAEJ4/ETASbFtem4cpeadl15peCijmF1gsTSZkwCEw/s1600/AV8C-driver-front.jpg" /></a></div>
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In contrast to the cheaper stamped steel frame of the Eminence, we have a very solid cast frame. There is no dust cap here. An accordion cloth surround ensures very long life and very control of the cone edges. </div>
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The compression driver is integral to the design. Shown above is the back of the phase plug and you may also notice the copper shorting ring. This arrangement provides much better alignment of the acoustic centres.</div>
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<a href="https://2.bp.blogspot.com/-H50abK9I7CI/WTS97fUgg1I/AAAAAAAAEKU/NFbDEwqMktQbLYVyAEalk0RbY1DCSjbsACLcB/s1600/AV8C-proto.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="294" data-original-width="550" src="https://2.bp.blogspot.com/-H50abK9I7CI/WTS97fUgg1I/AAAAAAAAEKU/NFbDEwqMktQbLYVyAEalk0RbY1DCSjbsACLcB/s1600/AV8C-proto.png" /></a></div>
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Here we can see the best of both previous drivers. The woofer has a well behaved response, free from the problemmatic dips and breakup of the pro coax. We also have a very nicely extended top end without a falling response that needs to be corrected - this makes for a simpler crossover. Overall, a much more usable driver. Our first trial with a very crude crossover revealed a musical result - this is a very good sign. </div>
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Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com5tag:blogger.com,1999:blog-8689487740107692135.post-48219782592329090382017-06-04T00:49:00.000-07:002017-06-04T00:52:33.281-07:00Rythmik Audio Subs in Australia<div dir="ltr" style="text-align: left;" trbidi="on">
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<a href="https://1.bp.blogspot.com/-EGiBMJurYuw/WTOv6w3hx0I/AAAAAAAAEJE/BHIwP2B01Fstv9AAWpEAQ28aVhhGyO-BACLcB/s1600/DS1204.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="403" data-original-width="550" src="https://1.bp.blogspot.com/-EGiBMJurYuw/WTOv6w3hx0I/AAAAAAAAEJE/BHIwP2B01Fstv9AAWpEAQ28aVhhGyO-BACLcB/s1600/DS1204.jpg" /></a></div>
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As our long time blog readers will know, we've held Rythmik subs in high esteem for a long time. We first experience them back in 2006 and it was clear from the first moment they were fired up that these are articulate subs. The very clean and dry bass sound was clear even before they had been calibrated correctly. We are now Australian dealers for Rythmik subs. We offer their full range of kits and we also custom build finished subs, adding Australian-made enclosures to Rythmik kits. </div>
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Kits</h3>
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<a href="http://www.rythmikaudio.com/products2.html" target="_blank">Rythmik</a> kits include the driver and servo enabled amplifier. Both are integral to the design and sold together only. </div>
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We also offer flat packs, which are CNC machined to fit together and make for an easier build. These start at $399. Our standard designs are modestly sized 12" and 15" sealed subs, however, we can also create custom flat packs to suit any project. </div>
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We can offer:</div>
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<li>sealed </li>
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Custom made subs in Australia </h3>
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We manufacture subs in Australia based on the Rythmik kits. </div>
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<a href="https://3.bp.blogspot.com/-7k7hePvEfAk/WTO6jB7hC2I/AAAAAAAAEJY/cZiZq2q_OKUliL5DUl4eLwWaOKQBZG2JgCLcB/s1600/SUB15S-550.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="520" data-original-width="550" src="https://3.bp.blogspot.com/-7k7hePvEfAk/WTO6jB7hC2I/AAAAAAAAEJY/cZiZq2q_OKUliL5DUl4eLwWaOKQBZG2JgCLcB/s1600/SUB15S-550.jpg" /></a></div>
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This is one of our 15" subs (sealed). Neo magnets are concealed within the enclosure - they serve to attach the grille without unsightly old clips.</div>
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Featured here is a custom sub with dual 12" drivers, serving to reduce vibration. The client wanted a perspex cover instead of a conventional grille. Designed to match the existing entertainment cabinet in solid teak. </div>
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Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com0tag:blogger.com,1999:blog-8689487740107692135.post-67783496920435884232017-06-02T04:34:00.001-07:002017-06-02T04:43:24.658-07:00Active keyboard monitors<div dir="ltr" style="text-align: left;" trbidi="on">
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<a href="https://4.bp.blogspot.com/-cVDOcj1nJCc/WTEewJ55HHI/AAAAAAAAEHg/utSKhpoQ1XE28j7uje0buyNKQgihoD7CQCLcB/s1600/AL-monitor-front-angle.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="673" data-original-width="550" src="https://4.bp.blogspot.com/-cVDOcj1nJCc/WTEewJ55HHI/AAAAAAAAEHg/utSKhpoQ1XE28j7uje0buyNKQgihoD7CQCLcB/s1600/AL-monitor-front-angle.jpg" /></a></div>
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A client approached us to help upgrade their music system. This application was unique because the system would be connected to a digital keyboard. It could be argued that they wanted to create a live music experience at home, literally. Initially the interest was surrounding an accurate custom sub. However, when we heard about the monitors they would be using, the conversation changed. They were intending to purchase some monitors we had worked with before. We do come across quite a range of studio monitors in our consulting work. We proposed an alternative custom monitor and the result is seen here.</div>
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Drivers</h3>
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First we start with an Air Motion tweeter. Well regarded by many for their transparency and air. Of course, a tweeter with "air" in it's name must have air! And it must have motion, or it won't tweet very well. Bad attempts at humour aside, these are tweeters we don't normally use. One of the reasons is that many of them don't suit our designs. Another is that the response is often not as smooth as we'd like. However, in this case, we are using an active crossover which can overcome this aspect. Here we offered a choice between a silk dome and an air motion - they chose the latter. </div>
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For the midwoofer, we were looking for a smooth response with an extended top end. One particular driver that stood out is the Vifa NE180W-04 6.5" midwoofer. In this regard, this driver is exceptionally smooth out to around 14k with the exception of one peak around 5k. A curious thing about this particular driver is the very different response shown for the 8 ohm version. Differences are common here but usually they are quite subtle. <br />
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Also important here is the ability to achieve reasonable bass extension in a sealed enclosure - adequate to cross to a sub. Often our goals would suggest a 4" or 5" mid but the bass requirements suggested a larger woofer.<br />
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We also liked the open basket design, which is ideal in terms of avoiding any coloration.</div>
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Low diffraction design</h3>
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Given the intended use as a nearfield monitor, we considered that baffle edge diffraction on axis is actually more important than usual. We can easily see diffraction effects in our testing and crossover development, but in a typical real world situation, much of what we see becomes swamped by the room effects. In a nearfield situation, what we measure in our testing is closer to what the listener experiences. Room effects are more subtle.</div>
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In order to minimise diffraction, we did two things. Firstly, we carefully placed each driver with offsets optimised to tame the impact of diffraction on frequency response. Secondly, the baffle edges are rounded, which is especially important when using a small tweeter without any loading from a waveguide. </div>
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Here you can see the impact of the roundovers on a 1" tweeter that is mounted in the middle of the box. This is the extreme case, as this is the worst possible position for a tweeter.<br />
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Again we've removed the round overs and shown the impact of tweeter position only. We've now moved the tweeter into its final position. </div>
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Here we can see that now adding the round over further improves the smoothness (red). </div>
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Now with the woofer, we compare the impact of the roundovers with the woofer (below). As you can see, the roundover has less effect than with the tweeter. </div>
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We have little choice with placement of the woofer but some adjustment is still beneficial.</div>
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<a href="https://4.bp.blogspot.com/-lA2q0hWfwQE/WTFA7qKqZSI/AAAAAAAAEIM/0LgVml3y0AMs9qoZyptXVYjHt2n7Xcw9wCLcB/s1600/W-moved.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="292" data-original-width="550" src="https://4.bp.blogspot.com/-lA2q0hWfwQE/WTFA7qKqZSI/AAAAAAAAEIM/0LgVml3y0AMs9qoZyptXVYjHt2n7Xcw9wCLcB/s1600/W-moved.png" /></a></div>
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The black line shows how the final position compares to the middle of the box. There is not a great deal of difference but if we did have a crossover near 2k, we might be facing a challenge. </div>
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<a href="https://2.bp.blogspot.com/-5v3Py8bgIEI/WTFCCO-07II/AAAAAAAAEIU/CQH-EIDjb3scc_eMQTC3gK0Rl0M8qJdWACLcB/s1600/W-final.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="292" data-original-width="550" src="https://2.bp.blogspot.com/-5v3Py8bgIEI/WTFCCO-07II/AAAAAAAAEIU/CQH-EIDjb3scc_eMQTC3gK0Rl0M8qJdWACLcB/s1600/W-final.png" /></a></div>
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Now we've added the impact of the roundover and we can now see that it benefits us more than when placed in the centre. The dip around 2k is reduced, although the effect is subtle.</div>
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Enclosure</h3>
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The enclosure we used here is a braced 32mm MDF with separate sealed chamber for the tweeter and DSP amplifier. The walls are internally lined with 15mm rubber sheets. The result is when knocked, it's like knocking on a concrete column. The cabinet is internally filled with acoustic material.</div>
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Here we can see the raw farfield frequency response. In this measurement, the drivers are simply mounted in the enclosure and then tested with no DSP filters in place. We did test with a cap on the tweeter, so its low end roll off has been modified. </div>
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We see a gentle hump around 1k which is also seen in the datasheet. The woofer peak at 4.3k is related to the driver itself and is also seen in the data sheet. The smaller ripples in the woofer response are +/- 1 dB excluding the general trend.</div>
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The tweeter exhibits a rising response. This may be behind many of the subjective comments about these tweeters when this isn't corrected. In comparing it to other tweeters, we did notice what sounded like greater deal but also a thin sounding bottom end. This measurement explains what we heard. </div>
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Crossover</h3>
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Here we used a MiniDSP ICE amplifier with two channels for each speaker. The DSP crossover allows for very precise control.</div>
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One of the things we like about DSP active crossovers is the precision with which we can control the response. Although passive crossovers can be quite sophisticated, we find there are limits to what we can achieve, at times with a difficult compromise between response shaping and part count. With a DSP crossover, we typically have more filters than any design is likely to need. </div>
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<a href="https://2.bp.blogspot.com/-RzS9-KOSLFw/WTFLdUK8PtI/AAAAAAAAEIo/SebI9biy4tAZ0C-GXMGx6ZsTPjWQQXY-wCLcB/s1600/DSP-axo.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="292" data-original-width="550" src="https://2.bp.blogspot.com/-RzS9-KOSLFw/WTFLdUK8PtI/AAAAAAAAEIo/SebI9biy4tAZ0C-GXMGx6ZsTPjWQQXY-wCLcB/s1600/DSP-axo.png" /></a></div>
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Here we have now achieved a response of +/- 2 dB.</div>
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<a href="https://2.bp.blogspot.com/--2lBAZ4XK_g/WTFMCjei3oI/AAAAAAAAEIs/uDypvcrELQggGPlXEXXHqxIYB4EdeQDFQCLcB/s1600/DSP-configs.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="292" data-original-width="550" src="https://2.bp.blogspot.com/--2lBAZ4XK_g/WTFMCjei3oI/AAAAAAAAEIs/uDypvcrELQggGPlXEXXHqxIYB4EdeQDFQCLcB/s1600/DSP-configs.png" /></a></div>
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We also evaluated various settings to adjust the tweeter level. In this case, we found that a near flat treble response produced the best results and the most balanced sound. </div>
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One the crossover design work was complete, the original character of the tweeter changed significantly. The exaggerated top end detail and thin sound was replaced with a very balanced sound. Still, there was no question that its detail was very appealing. </div>
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Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com0tag:blogger.com,1999:blog-8689487740107692135.post-78712943887806581672017-06-01T01:33:00.003-07:002017-06-01T01:33:57.010-07:00Are you waiting for a reply?<div dir="ltr" style="text-align: left;" trbidi="on">
We receive daily inquiries through our web form, both on the blog and our main website. We normally aim to reply to all messages the same day, if not the following.<br />
<br />
In some instances, we find out that our reply has not been received.<br />
<br />
If you don't receive a reply within 48 hours, please let us know.<br />
<br />
Just today we received an email notifying us that this is the third attempt to contact us. In this case, we had replied to all of three messages.<br />
<br />
Aside from our web form, we can also be contacted through our <a href="https://www.facebook.com/RedSpadeAudio/" target="_blank">facebook page</a>, which can avoid problems sometimes encountered with spam filtering.<br />
<br />
When contacting us, consider including your mobile number which provides a secondary option to check our reply is received.</div>
Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com0tag:blogger.com,1999:blog-8689487740107692135.post-74334632419909240042017-05-25T19:27:00.000-07:002017-05-25T19:37:38.683-07:00Celestion Ditton 66 mod<div dir="ltr" style="text-align: left;" trbidi="on">
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Celestion Ditton 66 is a speaker that many enthusiasts have refurbished. </div>
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<a href="https://1.bp.blogspot.com/-d8DHnyp2S-w/WSd_7acG8EI/AAAAAAAAEGA/ZOEEi-5_O-EOCg-mSTVGdu0HX-21VHHeQCLcB/s1600/Celestion-renovation.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="1125" data-original-width="550" src="https://1.bp.blogspot.com/-d8DHnyp2S-w/WSd_7acG8EI/AAAAAAAAEGA/ZOEEi-5_O-EOCg-mSTVGdu0HX-21VHHeQCLcB/s1600/Celestion-renovation.jpg" /></a></div>
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A client came to us with a modified version. All the original drivers
had been replaced with new drivers that its owner hoped would work well. </div>
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As you can see, the front baffle has been modified with chamfered edges, which is a good idea, especially with a 3/4" tweeter which is highly sensitive to baffle edge diffraction. A Hiquphone 3/4" dome replaces the original along with a Morel midrange dome. Bass is handled by an Acoustic Elegance TD12X and is augmented by a Scan Speak passive radiator. </div>
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Testing the original crossover with new drivers</h3>
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Our first step was to test the existing crossover with the new baffle and drivers. As expected, we found a significant mismatch. </div>
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<a href="https://4.bp.blogspot.com/-BPGa5mgHY7M/WSeDqNh1kBI/AAAAAAAAEGY/LtHSRppRxConcTbp6CoJyOy7ekMD6flVQCLcB/s1600/PXO-original-TM.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="262" data-original-width="550" src="https://4.bp.blogspot.com/-BPGa5mgHY7M/WSeDqNh1kBI/AAAAAAAAEGY/LtHSRppRxConcTbp6CoJyOy7ekMD6flVQCLcB/s1600/PXO-original-TM.png" /></a></div>
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Above: Gated farfield response of the new drivers with the original crossover. Green: Mid dome Blue: Tweeter Black: Tweeter and mid network.</div>
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Here we can see a number of issues, all of them quite common when changes are made without a crossover redesign.</div>
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1. The dome has a broad hump in the low end of its passband, which effectively shelves down the treble at 1.4k by 3 dB.</div>
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2. The top end of the dome has a hump centred around 5k - this is critical because the intended crossover is here. </div>
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3. The treble response falls with rising frequency, resulting in a loss of perceived top end detail.</div>
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4. Mismatch between tweeter and mid levels.</div>
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5. The high and lowpass slopes overlap so that when combined, there is a broad hump from 4 - 14k in the treble response.</div>
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In short, we have a mess! </div>
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Moving on to the woofer, we can see that the existing crossover is asking a great deal of the dome mid. The red plot shows the farfield response with the nearfield shown above. </div>
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<a href="https://2.bp.blogspot.com/-4XiAO3PtvgI/WSeIC1X16jI/AAAAAAAAEGk/PRJETLCnn_ETfASO3T0kd6iCEYwJASUmgCLcB/s1600/PXO-original-W.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="262" data-original-width="550" src="https://2.bp.blogspot.com/-4XiAO3PtvgI/WSeIC1X16jI/AAAAAAAAEGk/PRJETLCnn_ETfASO3T0kd6iCEYwJASUmgCLcB/s1600/PXO-original-W.png" /></a></div>
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Choosing a crossover strategy</h3>
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There are a number of ways we can move forward with a project like this.</div>
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<b>1. Fully passive</b> - we could have simply redesigned the crossover. Many people like this option because it allows flexibility to use any amplifier. The downside here is that this requires many large and expensive components. Low grade caps and cored inductors are common to keep the cost down. However, with very high end Acoustic Elegance woofers, we would consider it a bad idea to bottleneck them in this way. </div>
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<b>2. Fully active</b> - this is a very popular option amongst DIYers. For this speaker it would have meant 6 amp channels (3 stereo amps). This option is most attractive where it allows drivers to work together which might have a difficult relationship in a passive design. </div>
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With this speaker, we have drivers that can easily work together in a passive design. However, we felt the best option overall was a hybrid approach.</div>
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<b>3. Hybrid crossover - passive tweeter/mid crossover actively bi-amped</b> - here the client was able to use the two amps he already had. We designed a new passive which is simpler than the original. It contains a high pass for the tweeter and a lowpass for the mid. This new and much simpler network made it feasible to use higher end compnents whilst sticking to a modest budget. </div>
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The new passive network</h3>
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This is the new tweeter/mid passive network:</div>
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<a href="https://3.bp.blogspot.com/-QYUUOlZBx-k/WSeBCmAsvvI/AAAAAAAAEGM/9bZu4a99YbcHtTixzUj2hiaM5i9nqDVBACLcB/s1600/PXO.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="317" data-original-width="550" src="https://3.bp.blogspot.com/-QYUUOlZBx-k/WSeBCmAsvvI/AAAAAAAAEGM/9bZu4a99YbcHtTixzUj2hiaM5i9nqDVBACLcB/s1600/PXO.jpg" /></a></div>
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We were able to make it simpler by omitting the midrange high pass network - this would be handled by the MiniDSP active crossover. A further advantage we like about this approach is that we can shape the response further without adding more passive components. </div>
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<a href="https://3.bp.blogspot.com/-C3FAG7AdhKY/WSeNE2cCPkI/AAAAAAAAEG0/_ek8Au_xdCcKtN-a1Wss5cpRIqnTJL5ZgCLcB/s1600/PXO-new-RT.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="281" data-original-width="550" src="https://3.bp.blogspot.com/-C3FAG7AdhKY/WSeNE2cCPkI/AAAAAAAAEG0/_ek8Au_xdCcKtN-a1Wss5cpRIqnTJL5ZgCLcB/s1600/PXO-new-RT.png" /></a></div>
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The response shown here includes DSP filters which provide further response shaping to the mids in particular. The response is <complete id="goog_1003668370">+/- 1.5 dB.</complete></div>
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<complete id="goog_1003668370"><span id="goog_1003668371"></span><span id="goog_1003668372"></span></complete><br /></div>
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<complete id="goog_1003668370"><span id="goog_1003668371">Augmenting the bass response</span></complete></h3>
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<complete id="goog_1003668370"><span id="goog_1003668371">An active implementation for the bass network has advantages that are well known. We avoid throwing money at big expensive passive parts and we also avoid wasting a great deal of amp power. Instead, we can use some of the headroom gained to augment the bottom end response. </span></complete></div>
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<complete id="goog_1003668370"><span id="goog_1003668371">The final response is shown here: </span></complete></div>
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<a href="https://2.bp.blogspot.com/-3U8WdqTDmPg/WSeQJzEIKiI/AAAAAAAAEHA/ZT88GVfCw9gws6DZcT0MPDIc_2SucQIOACLcB/s1600/PXO-new-TMW.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="285" data-original-width="550" src="https://2.bp.blogspot.com/-3U8WdqTDmPg/WSeQJzEIKiI/AAAAAAAAEHA/ZT88GVfCw9gws6DZcT0MPDIc_2SucQIOACLcB/s1600/PXO-new-TMW.png" /></a></div>
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Above 200 Hz the response is +/- 1.5 dB</div>
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Voicing</h3>
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In some speakers we find that a better subjective balance is achieved with a response that varies from flat on axis. This proved not to be the case here. This speaker sounds best with a flat treble response. However, the advantage of DSP implementations is that this can be easily changed. It's a simple matter of creating a different profile in which the bass and treble level can be modified.</div>
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Enclosure fill and the crossover</h3>
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Did you know that the enclosure fill and the crossover have a relationship with each other? This proved to be true with this speaker. We found the amount of fill in the original to be inadequate. We wanted to raise the crossover point as we knew it would benefit the dome and the woofer would allow it. The problem was that enclosure resonances were interfering with the top end response of the woofer. If it were a sealed enclosure, we could simply fill the whole box. However, to preserve the operation of the passive radiator, the amount of lining is limited. The very large passive bass network also limited the amount of lining that could be used. Removing it meant we could use more lining, resulting in a smoother top end response. </div>
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How does it sound?</h3>
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When it all came together, we noticed a well balanced sound. Smooth yet detailed top end with a nice integration throughout the entire range. The bass is clean, controlled and full bodied. Soon after our client had spent some time with them, we received a call. Usually this means there is a problem to solve - happy customers tend to enjoy listening to the music rather than call back to tell us about it. In this case the news was good. A happy customer describing the sound in very similar terms to those I've used. Even his wife commented on the improvement, noting that a particular track now sounds better than ever. </div>
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Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com0tag:blogger.com,1999:blog-8689487740107692135.post-57869600593731310662017-03-07T17:35:00.000-08:002017-03-07T17:46:01.678-08:00Melbourne room acoustic workshop<div dir="ltr" style="text-align: left;" trbidi="on">
Would you like to know how your room performs acoustically? Would you like to know how to measure your room and more importantly, how to understand what the results mean?<br />
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We're offering the chance to learn about room acoustics in the room that matters most - yours. We're offering this with a twist. In a typical room analysis session, we work one on one. To keep it affordable, we limit the time and cut to the chase, moving to the interpretation and what to do about it. You don't get the chance to learn how to take the measurements and how to interpret them.<br />
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Hosts wanted</h3>
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The best place to start is as a host. As a host you will learn about your room and come away with clear direction specific to your room, system and aspirations. Since all participants pay to enter, you pay less and you're getting more time. It also promises to be an enjoyable social event in the tradition of the Aussie audio GTG (get together) BBQ. <br />
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You need:<br />
<ul style="text-align: left;">
<li>an audio system that you enjoy with either music, movies or both</li>
<li>enough space for 5 participants to attend</li>
<li>availability from 10 am - 5 pm</li>
</ul>
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</h3>
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Participants wanted</h3>
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As a participant you get to learn about room acoustics in a system and room that is different to your own. If you've already used our room analysis service, then you may like to learn more about how it's done, as this involves content we don't normally cover. The best way to learn and retain what you've learnt is with a hands on approach. Every system and room is different.<br />
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If you would like to attend, either as a host or participant, register your expression of interest via our <a href="http://www.redspade.com.au/audio/contact.php" target="_blank">contact form</a>. </div>
Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com1tag:blogger.com,1999:blog-8689487740107692135.post-10709746039327752502017-02-24T19:36:00.001-08:002017-02-24T19:36:03.979-08:00PSE ultra passive crossover<div dir="ltr" style="text-align: left;" trbidi="on">
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Introducing the Ultra crossover:</div>
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<a href="https://4.bp.blogspot.com/-3sCldyJQqtU/WLD6gIcrtdI/AAAAAAAAEEs/oD23LMk4DG0TV_eAZLvkNHkCo7wAjZv3QCLcB/s1600/PSE-pxo-premium-ultra.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="https://4.bp.blogspot.com/-3sCldyJQqtU/WLD6gIcrtdI/AAAAAAAAEEs/oD23LMk4DG0TV_eAZLvkNHkCo7wAjZv3QCLcB/s1600/PSE-pxo-premium-ultra.jpg" /></a> </div>
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One of our PSE horn customers requested an ultra high end version of the passive crossover. These parts are in cost-no-object territory and they are among the best available. Where possible we used Mundorf Supreme Silver Gold and Oil caps. All cable runs are beneath the board, which serves not only to avoid visual clutter but also to assist with holding the caps in place. All caps are secured with adhesive rather than cable ties. Inductors are Mundorf foil types. </div>
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Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com0tag:blogger.com,1999:blog-8689487740107692135.post-53720382105244309692017-01-16T01:28:00.001-08:002017-01-16T01:33:35.154-08:00When your IR repeater is slow and unresponsive<div dir="ltr" style="text-align: left;" trbidi="on">
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So you've decided to <i>finally </i>get your act together and make your AV system spouse friendly. That might mean hiding all your audio equipment inside an entertainment unit <i>without </i>having to open the doors for your remote to work. Perhaps you've even installed it all in a dedicated cabinet completely hidden from view. You need an IR repeater.</div>
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<a href="https://2.bp.blogspot.com/-_T8-hbwCMPg/WHyQ2g73ENI/AAAAAAAAEDo/ZUBAfvL3pDgO5bZA1ZjypFZQPN12zhKfACLcB/s1600/IR-repeater.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="https://2.bp.blogspot.com/-_T8-hbwCMPg/WHyQ2g73ENI/AAAAAAAAEDo/ZUBAfvL3pDgO5bZA1ZjypFZQPN12zhKfACLcB/s1600/IR-repeater.jpg" /></a></div>
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Above: a wireless IR repeater.</div>
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The concept is simple. A receiver senses the signal from your remotes and then relays them to your equipment via a number of emitters attached to each device. Some relay the signal wirelessly, others via included cable or though existing HDMI or ethernet network cable. Integra AVRs also allow you to direct wire the signal.</div>
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Sounds so simple, what could go wrong?! If you use Foxtel, you should be aware that not all IR repeaters are compatible, so check before you buy. Another potential problem is interference from devices near the IR receiver. When this occurs, you'll notice that the response is very slow. You may have to press a button multiple times and it appears to work very slowly, very hit and miss.</div>
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To test if this is your problem try this:</div>
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1. Move the IR sensor away from all other devices</div>
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2. Aim the remote at the sensor at close range (say 100mm away) - aim carefully</div>
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3. Does it work now? If so, gradually move the unit closer to its intended position. You may find that the problem comes back as it gets close to other devices.</div>
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4. Is there an alternative position that avoids the problem?</div>
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5. The sensor may require shielding. A quick experiment is to line it with aluminium foil as shown below.</div>
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<a href="https://4.bp.blogspot.com/-DTTnvYa5iO0/WHyQ26t6xOI/AAAAAAAAEDs/5MJGjuwL8lQw_NQn7zxLJB7uyrpUO02EgCLcB/s1600/IR-repeater-shield.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="https://4.bp.blogspot.com/-DTTnvYa5iO0/WHyQ26t6xOI/AAAAAAAAEDs/5MJGjuwL8lQw_NQn7zxLJB7uyrpUO02EgCLcB/s1600/IR-repeater-shield.jpg" /></a></div>
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We know, it's not pretty! We suggest this not as a long term solution but as part of your troubleshooting process. If this solves your problem, then you know you have an interference issue. If you have DIY inclinations then you might consider a longer term mod, like installing the IR receiver in a DIY metal box or you might come up with some simple DIY shielding. Many at this point would simply take the device back. </div>
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Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com0tag:blogger.com,1999:blog-8689487740107692135.post-78898231011170566102016-08-01T23:01:00.000-07:002016-08-01T23:01:44.216-07:00What drivers do you use?<div dir="ltr" style="text-align: left;" trbidi="on">
One of the questions we are most often asked is "what drivers do you use?" We get this question most often from DIYers. We understand why people are asking. It's one of the first questions a DIY enthusiast will ask to gain a feeling for the quality of the speaker. It's a short cut to making a comparison to other products on the market.<br />
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There are many problems with trying to evaluate a product in this way. Here are some<br />
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1. False sense of security</h4>
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Using drivers that are DIY favourites does not guarantee a good result. There are many poor or average implementations of very good drivers. We've experienced many. We've had customers come to us with speakers that should perform much better. They use very high quality drivers but it's very easy to overlook the importance of crossover design.<br />
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2. Undiscovered gems</h4>
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There are many undiscovered gems. Many DIYers are uneasy about heading into unfamiliar territory. This is why most head onto the forums and watch what others are building. The decision to go ahead comes after a lot of reading.<br />
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Yet there are many drivers unknown to DIYers with very good performance. Many are actually better than the drivers that get rave reviews. Generally, this isn't realised because comparisons aren't made very often. And when a comparison is made, it may only apply to the specific implementation.<br />
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3. OEM drivers are not available to DIYers</h4>
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Some drivers can only be purchased in commercial quantities. These may carry the branding of the loudspeaker manufacturer or they may not. The drivers may be modified in some way to make them suit the application. It could be a superficial change like a different coloured woofer cone. It could be a modification to the TS parameters to make it better fit a particular design. In some cases, the change is so significant that it effectively becomes a new and unique driver. It may share the same basket or cone but be radically different in the areas critical to performance. <br />
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In a DIY project, it often pays to play it safe. You don't want to buy some unknown driver and find out it's a dud. However, when we put a product onto the market, we always test it first. The easy way is to go with something familiar but often we are looking for something more. So we take a risk and try unfamiliar drivers and very often if you are smart about it, this can be very worthwhile. <br />
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And then again, sometimes you hit a dead end. Earlier this year we did some experiments with some new mids for PSE-144. We were hoping to find some midrange drivers for a signature edition. Unfortunately none of the drivers we tested were even able to match our current driver. <br />
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Most of the drivers we use are OEM. When it comes to woofers are top models use Acoustic Elegance drivers. </div>
Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com0tag:blogger.com,1999:blog-8689487740107692135.post-29068315198015665782016-07-14T03:00:00.000-07:002016-07-14T03:06:44.702-07:00DIY point source horn pre order<div dir="ltr" style="text-align: left;" trbidi="on">
We've had a good response to the concept, so we've now moved on to start developing our DIY point source horn kit. Here is our initial concept sketch:<br />
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<a href="https://1.bp.blogspot.com/-nDev_W796pI/V4djwj1fX9I/AAAAAAAAEAc/06hUfBnuI4M8vRZRhZwfdLmGd0HtLG7YwCLcB/s1600/PS-60-1.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="https://1.bp.blogspot.com/-nDev_W796pI/V4djwj1fX9I/AAAAAAAAEAc/06hUfBnuI4M8vRZRhZwfdLmGd0HtLG7YwCLcB/s1600/PS-60-1.png" /></a></div>
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<a href="https://2.bp.blogspot.com/-JtoCR1M_3nU/V4djw8lbpdI/AAAAAAAAEAg/uBsF_RdChP8P1Rrhm-rELwX9gVHT05OVgCLcB/s1600/PS-60-2.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://2.bp.blogspot.com/-JtoCR1M_3nU/V4djw8lbpdI/AAAAAAAAEAg/uBsF_RdChP8P1Rrhm-rELwX9gVHT05OVgCLcB/s1600/PS-60-2.jpg" /></a></div>
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The horn is 500mm wide and has a 60 x 60 degree beam width. Kit will include an integral stand along with an assembly jig that will make it easy to glue the panels. <br />
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Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com15tag:blogger.com,1999:blog-8689487740107692135.post-19340486903678656072016-06-01T18:49:00.001-07:002016-06-01T18:57:11.992-07:00EOI: DIY point source horn kit<div dir="ltr" style="text-align: left;" trbidi="on">
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The last time we talked about offering a point source horn kit, it turned into something quite spectacular. It attracted a crowd and this launched PSE-144:</div>
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<a href="https://1.bp.blogspot.com/-qdSAIB-G3kA/V0-MLBHb30I/AAAAAAAAD-0/UuVKBovS3W4jA-eyde_Q1_C7PeX9juLrwCLcB/s1600/PSE-144-front-full-red.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="400" src="https://1.bp.blogspot.com/-qdSAIB-G3kA/V0-MLBHb30I/AAAAAAAAD-0/UuVKBovS3W4jA-eyde_Q1_C7PeX9juLrwCLcB/s400/PSE-144-front-full-red.jpg" width="303" /></a></div>
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We realise some people like to roll up their sleeves and build something. We also realise, not everyone has the budget for a statement horn with Ferarri curves. </div>
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Now we're again considering launching a DIY kit. This kit would be offered on a pre-order basis, including flat pack, mid drivers and an option for a passive crossover. Please keep in mind some details of the offer are likely to change as we progress. </div>
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We've not yet set a price, but we believe it will sit in a range that most can afford.</div>
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If you'd like to jump on board, please <a href="http://www.redspade.com.au/audio/contact.php" target="_blank">contact us to express your interest</a>. We do require a certain number of adopters to make the project feasible. The price gets better when the group gets bigger. </div>
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<a href="https://2.bp.blogspot.com/-DDlvAInH5o8/V0-R4DNgS9I/AAAAAAAAD_M/Stx_p9s1GooxoHTlphocVth5SztIsPRqACLcB/s1600/prototype-rear.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="https://2.bp.blogspot.com/-DDlvAInH5o8/V0-R4DNgS9I/AAAAAAAAD_M/Stx_p9s1GooxoHTlphocVth5SztIsPRqACLcB/s1600/prototype-rear.jpg" /></a></div>
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Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com1tag:blogger.com,1999:blog-8689487740107692135.post-72960963213670580812016-04-07T01:11:00.002-07:002016-04-07T01:14:32.919-07:00Introducing AV10 and AV12<div dir="ltr" style="text-align: left;" trbidi="on">
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We're now launching AV series. This is a range of speakers designed with serious home theatre in mind. Shown here is AV10 on the left and AV12R on the right. These will shortly be installed in "the red room" ready for audition. </div>
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AV series concept</h3>
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AV series represents smart design with serious home theatre enthusiasts in mind. All models are intended to be able to reach THX reference levels even with modstly powered AV receivers. In fact, even our smallest speaker in the range can be expected to exceed the capability of nearly all other speakers on the market even where they are given the advantage of a very high powered amplifier. </div>
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Design brief</h3>
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We've designed AV series to offer:</div>
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<li>exceptional value</li>
<li>extreme output capability</li>
<li>vocal clarity</li>
<li>neutral and accurate sound</li>
<li>consistency across a considerable listening area</li>
<li>superior dispersion control</li>
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Options</h3>
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AV series is offered as DIY kits or fully finished. Kits include:</div>
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<li>DIY Flat pack </li>
<li>Drivers</li>
<li>Terminals, screws, hardware</li>
<li>Pre built handle made passive crossovers (active versions available by request)</li>
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Finished versions come with a choice of finish:</div>
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<li>Sprayed satin 2 pack finish</li>
<li>Sprayed piano gloss black</li>
<li>Selected veneers in satin or gloss finish</li>
<li>Custom finishes available also</li>
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Photo above shows kits that have been assembled with textured black finish. This is not the finish that we provide with the finished version but demonstrates the finish that is easiest to achieve. This finish is quite accessible to the average handy man with no special tools.</div>
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Paul Spencerhttp://www.blogger.com/profile/07514836858344391753noreply@blogger.com0