January 23, 2013

HE2 dispersion

HE2 has now been measured for dispersion:

The woofer has fairly wide dispersion which then narrows above 1k. The waveguide and compression driver combination narrow their pattern gradually towards higher frequencies. A robust compression driver which can run below 1k has been chosen, to allow freedom with the crossover. This makes the smooth handover shown here possible. Some beaming is shown around 15k, meaning there will be some loss of high frequencies radiated to the room. This is not a big issue.

Overall, this is a good result.

January 20, 2013

S3 prototype dispersion measurements

S3 measurements confirm very good dispersion control. Constant directivity has been achieved and pattern control has been maintained down to the Shroeder frequency of typical listening rooms. The - 6 dB line shows the nominal coverage angle - in this case 80 degrees nominal (or 40 degrees from the central axis as shown on the sonogram). The results have been gated and normalised. The floor reflection has been gated out and normalisation adjusts the axial measurement to a flat response. As a result, the sonogram shows dispersion rather than frequency response. One could achieve a similar result by using EQ to get the axial response flat, but this method is much quicker.



The vertical coverage is a little narrower than anticipated and this is a matter for further investigation. My initial supicion is that the dip around 5.5k may skew the result.

What is particularly pleasing with this result is that the beaming often seen before pattern control is lost on the bottom end, has been eliminated.

January 10, 2013

6 driver mid version

6 driver mid version:

Both versions, with 4 mids and 6 mids, are viable options. Currently working on variations and assessing the merits of both versions.

You get a little hint from the photos that there was some challenge in getting the side mids in place. It's not easy to get the mids this close for a high crossover point, and have 6 of them!

January 6, 2013

S3 prototype - continued

This is the second horn:

I used polyurethane glue instead of PVA this time for its superior strength and expanding characteristic, so the bond is more forgiving with imprefections.

This is a quick 'n dirty test prototype to test and refine the design. I will be testing some variations before finalising the design. 

Please do not take this as an indication of the build quality of the S3 kit!

The kit will be machined in a factory, rather than using the manual methods you can see here.

January 3, 2013

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Accuton + Scan Speak + Acoustic Elegance DIY speaker

Quick heads up about a very nice DIY speaker that's up for sale. This one is designed by Beau in Queensland Australia and it's a very ambitious build!

Scan Speak tweeter (previously Peerless HDS - a very nice driver)
6" waveguide
Accuton midrange
Acoustic Elegance TD10 subs + passive radiator

If you'd like to enquire about these speakers, you can contact me via the contact form link (top right side) and I'll send your query through to Beau.

Or you can reach him direct via this thread:

SNA thread

Comments from Beau:

The speakers were constructed over a 12 month period in 2010/2011. The cabinets are of multilayer construction, MDF/Ply/MDF and are over 1 1/2 inches thick in places.
The front baffles are finished in a high gloss two pack white whilst the sides are finished in a chocolate brown satin timber laminate.
The driver complement includes the Scanspeak D2608 tweeter, loaded by a 6" waveguide,

This hands over to arguably one of the finest midranges available. Manufactured by Accuton, it uses a huge Neo magnet coupled to a ceramic cone.

The bass is handled by 2 10" Woofers per side, custom made by Acoustic Elegance in the United States. They are aided by a pair of 15" passive radiators per side. 

Passive crossovers with low DCR custom made inductors and wirewound resistors make it all sing, with a rated sensitivity of around 90db 1w/1m and power handling well in excess of 400 watts they get LOUD.

Enquiries around $4000 welcomed. 
Location, Far North QLD.