March 31, 2011

DIY point source horn

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.



Drivers










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)

Simulations

Hornresp has proven more effective than expected for the mid drivers.

Sims vs measurements >
Hornresp lessons >

Construction

Build photos - part 1 >
Build photos - prototype complete >


10 comments:

  1. I am working on something similar using the components of a U15 and a modified DCX2496.

    http://totravelisbetterthantoarrive.wordpress.com/2010/06/13/the-next-to-last-diy-speaker-project/

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  2. Link added. The more out there, the better!

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  3. Paul, your project inspired me to have a listen (and measure) some Danley Synergy/Tapped horn speakers before either buying some or make my own. The UK importer is not far from me so I made an appointment to hear their speakers both at their small warehouse (8m x 7.2m x 5mhigh) and at the partner's home (5m x 5m x 2.5mhigh). The speakers demoed in the warehouse was a pair of SH-50 on their own and with a pair of TH-118 subwoofers, followed by a pair of SH-95 on their own and with the TH-118 subwoofers. The following week, I heard a pair of SH-100B speakers at the partner's home. The sound quality in all cases was the best I have ever heard. The words that best describe the sound are : clarity, coherence, ease, naturalness, smoothness, and realness. It was the closest I have ever heard reproduced sound to real sound. The measurements (with Praxis and OmniMic) were if anything better than published on the Danley Sound Lab website. As a result, I am totally sold on Synergy/Tapped horn speakers with subwoofers as the best way to get accurate sound reproduction in a domestic environment. I will follow your progress with great interest.
    Tony Seaford, MARTON MUSIC, Lancashire, UK

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  4. Any chance of getting a hold of drawings to this fabulous build..?

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    Replies
    1. I am considering offering a kit based on this design. This may happen in the near future, with an announcement going out to those who expressed interest.

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    2. A kit would be awesome, please keep us posted.

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    3. A kit would be awesome, keep us posted.

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  5. Please consider to offer specs and drawings also. You would have customers for this build all around the world, and shipping can kill any good initiative...

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  6. Cool design
    I'm interested in learning as am building p.a .
    I have two double W bins at present for bass but am a carpenter so keen on day.

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    Replies
    1. Hi Andrew,

      There is a kit coming. I wrote about it here:
      https://redspade-audio.blogspot.com.au/2016/06/eoi-diy-point-source-horn-kit.html

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