Update:DIY point source kit
This point source horn combines a unique mix of features that make it very appealing. It has the extremely high efficiency of horns and the associated dynamics and clarity, but without the lack of coherence due to the coaxial design. It also features constant directivity. Here is my first prototype:
A compression driver is loaded into a conical horn at the apex and four 5" closed back mids are loaded into the same horn via ports. The mids operate in a bandpass configuration, where the air trapped under the cone acts as a compression chamber and provide acoustic filtering. This means harmonic distortion is also filtered, resulting in very low harmonic distortion.
S1 - prototype 1
My first prototype was a simple 60 x 60 degree conical horn with four 5" closed back mids, a compression driver at the throat and an 18" pro woofer. It performed very well, confirming the simulation was correct. It gave me an appreciation of what a point source horn can do in a small room. I enjoyed the effortless dynamics, unlimited clean output and midrange detail.
S2 - prototype 2
Now more confident that I have a good grasp of how this works, I started a more ambitious version with 90 x 45 degrees coverage and the 6 drivers necessary to retain the bottom end extension. This version has a second flare angle for an improved polar response and was much more difficult to build.
Driver selection >
Tweeter: B&C DE250 1" compression driver (1 - 18k)
Midrange: Pyle PDMR5 5" closed back (230 - 1k)
Woofer: Eminence Magnum 18LF (35 - 230)
(Subs: Rythmik Servo tapped horns - future project)
Hornresp has proven more effective than expected for the mid drivers.
Sims vs measurements >
Hornresp lessons >
Build photos - part 1 >
Build photos - prototype complete >