Index of DIY Synergy and Unity Horns

Discussion in 'Waveguides and Horns' started by BillWaslo, May 13, 2012.

  1. A collection of DIY Synergy and Unity Horns based on the Tom Danley designs. Thought I'd try to collect links to all here in one place.

    Here are various threads that I am aware of from around the internet in which people describe their home-made Synergy or Unity horns. In no particular order--

    William Cowan's at http://cowanaudio.com
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    Cowan has also done a lot of experimenting with a Unity Horn, details at his web site.

    John "Patrick Bateman"'s Synergy horns... some made for a car dashboard! At http://forum.audiopsychosis.com/viewtopic.php?f=3&t=75&sid=89651792d84acfa7f7509720c3cb5e70&start=10#p520
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    Paul Spencer's at his web site
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    A LOT of extensive work and good info to be found at his blog site:
    http://redspade-audio.blogspot.com/2011/03/diy-synergy-horn.html

    mtg90's "very low budget DIY synergy" horn, with some pretty impressive results at:
    http://larchive.avsforum.com/www.avsforum.com/avs-vb/showthread.php?t=1405783
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    A You-tube demo of it:
    http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&ved=0CF0Q8AEwAw&url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3D5rAI-uJcblg&ei=QlbHT52ID-Xi0QHavrWwDw&usg=AFQjCNFjp9o5POJ3V2LBQ7ftJiFeUCI9ZQ&sig2=h3fg6z9SYvdfF45euPi3yA

    Johnbomb's Unity Horn build using Alpha6 and BMS4550 drivers, with measurements, detailed at:
    http://www.avsforum.com/avs-vb/showthread.php?t=1407483&highlight=johnbomb
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    lilmike's build. (Is there a thread describing this besides at
    http://www.diysoundgroup.com/forum/index.php?topic=19.msg168#msg168 ?)
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    davey t's (and also James Folkes') at
    http://forum.speakerplans.com/peace-love-and-unity-horns_topic29253.html
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    jmorken showing some really nice results at
    http://www.diyaudio.com/forums/multi-way/195955-unity-horn-budget-drivers-active-x-over.html
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    dnewma04's beautifully carved Unities at
    http://www.audiokarma.org/forums/showthread.php?t=278515
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    JLH over at diyAudio has written a lot and given a lot of help on Unity/Synergy operation.
    http://www.diyaudio.com/forums/multi-way/88237-suitable-midrange-cone-bandpass-mid-unity-horn-19.html#post2441865
    (I couldn't find photos of his build, diyAudio is Slooooow tonight!)

    Dag Johansen at
    http://www.diyaudio.com/forums/multi-way/168075-compression-ratio-new-build.html
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    Mine:
    http://www.diysoundgroup.com/forum/index.php?topic=19.0
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    Tom Sheerin's Unity builds, see http://www.jhsaudio.com/unity2.html
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    Tony Seaford's Synergy build, check out the nice looking cabinet!
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    If I'm missing any, I apologize -- set me straight and I'll add them to the list!
    If you've done any work on Synergy or Unity DIYs, post some pics!

    Thanks,
    Bill
     
  2. Nope - no build thread on those. That's the most airplay I've given them.


    To be honest - though I learned a bunch from the process, that's about all the airplay that project was worthy of...
     
  3. Is it licensed from Tom?
     
  4. a few random comments:

    - the whole reason I had an opportunity to learn about the Unity was that I worked for a dying dotcom, and we didn't have much work to do. A bunch of my coworkers spent their time playing videogames and waiting for the axe to fall. I spent half my day applying for jobs and the other half studying Danley's patents. That was over a decade ago.
    - 80% of my Unities haven't turned out very well, likely because I keep trying to shoehorn them into such a small horn. My most successful Unity horn was the one using the BMS 4540ND and the Tangband 2" drivers. That sounded really good and imaged like nothing I've heard in a car. It was also one of the few that used an oblate spheroidal curve
    - I'm slooooowly building some paralines, using the same woofers that Bill Waslo is using in his Unity horn. My sims don't look promising, but I'm not convinced that there's a software program that can properly simulate a Paraline. So this is a bit of a 'stab in the dark.' I have a spreadsheet uploaded to my thread named 'sunshine' on diyaudio that will give you the dimensions. The Paraline is neat because it allows you to fold a really long horn into a small footprint. There's nothing magical about it, it's simply a novel way to fold a horn.
     
  5. Patrick,

    How would you do a paraline to just shorten a normal Unity/Synergy. For instance, I need about 1.5" more delay on my tweeters to make my Synergies linear phase, but the cabinet won't accomodate putting an extension on the CD mount. Could that be done with a paraline structure?
     
  6. To get a delay of 1.5", or a fraction over a tenth of a millisecond (13.5"), just add a Paraline that's 3" tall by 1.5" wide. The reason that you'll use one that's 3" tall is because the sound expands radially, so a 3" tall Paraline has a pathlength that's 1.5" long. (The radius of the disc that's folded inside of the Paraline.)


    Having said that, I'd be careful about using the Paraline for pure delay, unless you have DSP handy. We don't have an easy way to model these things 100%, but from what I can see in Hornresp, they *seem* to be more sensitive to spacing than a regular Unity horn.


    Here's my hypothesis on why this is:


    In a regular Synergy or Unity horn, the compression driver does not 'see' the midrange horn, if you size it properly. Basically there is a 'sweet spot' along the length of the conical horn where the horn is large enough that it's no longer providing much gain for the compression driver. So the sound of the compression driver is basically constrained into a cone, and it sails right past the midrange ports.


    In a Paraline, we don't have that luxury. The volume of the horn is so small where the midranges tap in, they're *definitely* visible to the compression driver.


    That gives us two options I think:


    option a - get the drivers really really close together, so close that they're within 1/4 to 1/3 wavelength at the xover point. With an xover point of 1500hz, that's about 2.25" center to center. This is tricky, but do-able with 2" midrange like yours. The downside to option a is that it does not account for the delay that exists at the resonance of the two drivers. Danley has hinted around about this, and it seems to be one of the reasons he likes the BMS 4550 over comparable options. (Check out the impedance curve of the 4550 and you'll see what I mean.)


    option b - just stick the midranges outside of the Paraline. This is what all of the commercial offerings do. For instance, in the smallest VTC box the Paraline has a diameter of about 4", so the center-to-center spacing is about 8". That type of spacing would require an xover of about 422hz (if we ignore the delay imposed by the various resonances.) Obviously, 422hz is way too low an xover, so Yorkville and VTC use DSP delay on their boxes.






    Obviously, the easiest way to get everything in phase is to simply build the darn thing, and then measure the impulse response. One very nice thing about the Paraline is that you can move the midranges around on the horn by simply replacing the bottom plate. You can literally build that plate in five minutes. It's way way easier to fabricate than a conical horn, and it really makes it easy to experiment with the phase response without wasting aeons in the garage.


    At the crossover point, moving the midranges an inch can spell the difference between a peak and a dip in the midrange, so having the ability to move the midranges so easily is really nice. If I had to hazard a guess, I believe the only reason that Yorkville and VTC don't put the midranges on the Paraline is that it severely limits your power handling. Due to the very small sizes involved, any midrange larger than 2-4" is basically impossible.


    Unless you put the compression driver UNDER the midrange, like this:


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  7. Thanks, PB. What I meant was a way to only delay the compression driver; while still using the usual on-waveguide mount for the mids. What would the inside of a paraline that only added delay look like?

    And is it feasible to make it present a spherical wavefront to match the waveguide's expansion angle? I'm thinking a donut shaped ring in the center layer would add extra length toward the outsides of the throat; possibly making that kind of wavefront.
     
  8. Here is one of a set of 2-way Synergy horns that Tony Seaford in UK is building using baltic ply. These were calculated using my spreadsheet (see other thread) and the horn is about the same dimensions as mine. Tony is using Morel MW166 for the bass/midrange and DE250 for the tweeter with a crossover of around 1kHz. The top and bottom are removable for easy access to drivers.
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    He has a crossover going and reports the response uniformity around the coverage area is very good. Nice looking construction, isn't it? This wouldn't look bad at all in a music room.

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    I'll post measurements (or maybe Tony will?) when I get them. Tony is working up the second one right now, so we probably won't hear from him for a while if his experience is like mine and he ends up not wanting to do anything other than listen to them for a while!

    Maybe we can get him to share his outer cabinet cutting details?
     
  9. Here's some more shots of Tony's Synergies. He's using them variously with W-Frame woofers or Tapped Horns.
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    Here's a shot of the 1m response of the horn by itself.
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    Tony calls his build the "Multi Entrant Horn" or "MEH" (! ;) ). That doesn't seem to be his opinion of the sound, though. To quote:
    "Very clean coherent sound. Very little sound outside the beam angles. Congratulations to Tom Danley."
     

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