Why are their so few synergy/unity builds??


2012-10-27 8:45 am
Been doing a lot of internet searching regards synergy/unity horns and a lot of seemingly successful threads seem to go dead at critical points with pictures photos missing.

Even you tube put a block on one due to copying soundtrack (sum geezer must have complained)

Most that start the threads are quite impressed initialy with the sound that they get.

So whats happening

Are they good /great/notso good???? PA only or domestic hifi or home theater.

I am considering building one but only if the components I have will sufice (another thread) for home hifi
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They're unsurpassed in terms of sound quality and soundstage/imaging, if done well. It turns out that the multiple entry design is actually fairly forgiving, as long as you don't put a port all the way across a horn wall or or place them too far away from the horn throat to achieve a good low pass or band pass (in the event of using midrange drivers, which I don't recommend--go two-way instead).

I recommend a 2" full range compression driver at the throat and a fairly large mouth dual-flare conical horn (or modified tractrix)--as large as you can stand, then you'll have a full-range unity design--like this one: https://community.klipsch.com/index.php?/topic/161404-a-k-402-based-full-range-multiple-entry-horn/

The main limitations seem to be
  • They tend to be big (if you're using it to get directivity below 1kHz, and especially if designed for a narrow pattern)
  • Big horns aren't all that easy to build and molded horns big enough are rare and expensive
  • It's not easy to get a super smooth HF response - big CDs or cones used there are rough above 10kHz and tend to beam up there a LOT. That's actually not a big deal considering what adult male hearing limits really are, but looks bad on graphs
  • Their crossovers are hard to do (if passive) and typically require response measurement equipment and a littl signal processing or circuit smarts in either case. Not for the impatient newbies!
  • The concept is patented, so there aren't any inexpensive units or kits for people to just buy

Givena all that, they are still worth it, but maybe not enough so when compared to a SEOS or Pi based kit..
The main limitations seem to be:

  • ...molded horns big enough are rare and expensive
  • It's not easy to get a super smooth HF response - big CDs or cones used there are rough above 10kHz and tend to beam up there a LOT.
  • The concept is patented, so there aren't any inexpensive units or kits for people to just buy

1) Perhaps the large horns that are appropriate are not as rare and expensive as you might think.

2) The HF response above ~7 kHz is a function of the compression driver phase plug. HF coverage is much, much better than bullet tweeters.

3) USPTO shows that Unity horns are no longer patented as the patent holder has twice allowed the patent to lapse due to nonpayment of maintenance fees; the patent is now expired (USPTO).
What waveguides are you thinking about then? The big Klipsh is $$k

I wouldn't personally even consider bullet tweeters to be anything to compare to! But Ive not seen evidence of any 2" drivers that couldnt be said to beam in the "last octave" if used in a wide (i.e., not huge for home use) horn. The pattern width has already been determined inside the driver's narrow thouat angle.

Many thanks for pointing out the expiration on Unity!

Curious why that happened... does Sound Physics then no longer exist as an entity to be able to renew it??
Go for it, Bill!

I have been wanting to try a corner loaded 2-way synergy for my HT room, with a center option. My room is quite small and narrow, sidewalls should be used for benefit. I believe that this is a quite common situation. The other option is to make corner-line arrays..., but theoretically I like concentric idea better. I think that I will make a plywood proto when the snow melts away... I don't need the high spl of a compression driver, a robust 1" dome should be ok, I have some dashboard-Vifas somewhere...., a minidsp 2x4 for testing.

For a synergy in a corner (triangular cabinet) two bass drivers can be placed below and over the tweeter. This way the tweeter can be pushded near the apex.
Most of the issues with the 10-20 kHz octave in 2" compression drivers is diaphragm material-related. If you read the Truextent white paper(s), you'll see that titanium (Ti) undergoes breakup modes badly, aluminum (Al) not quite as badly, and beryllium (Be) almost not at all. Your choice. Not having midrange drivers and another set of crossover filters and holes in the horn is a big advantage in simplifying the designs...if not fidelity enhancement.

Read the Klipsch K-402 thread linked above for more horn choices. There are more choices becoming available.

I don't know how the Unity patent situation played out. It looks like money problems or perhaps a lack of interest in protecting that particular IP over the other inventions, i.e., tapped horns and Paraline manifold combiners. The current Danley Synergy patent apparently controls only the approach to using passive crossovers and location of the ports to avoid nulls. Otherwise, the prior Unity patent apparently held the real IP.

I don't believe that Tom himself wants to discourage DIYers doing home hi-fi, just direct competitors in the PA business. I think that all the projects we're seeing here and elsewhere doing DIY basically honor that wish. I saw a lot of improvements in the approach to simplify the complexity and increase the utility of home hi-fi versions--over the commercial PA versions that aim for extremely high SPL and power sharing among drivers.

I know that the things that I've learned from Roy Delgado (Klipsch) on how to do large 2-way fully horn loaded designs have led to outstanding improvements in the hi-fi performance, e.g., the home hi-fi Jubilee and its variants. Many of those lessons are found in the K-402 thread combined with Tom Danley's Unity horn idea. It's just another approach that yields really good results.

Your multiple entry design is quite good but more intensive in terms of required woodworking and passive network design/implementation for lowest costs. If you're willing to accept a slightly higher price point for the horn, the K-402-based design opens up simple and straightforward choices that perform really well versus anything marketed for home hi-fi...and full range, avoiding the vented bass box.

Now that the source of the miniDSP noise issue has been identified (USB power supply noise) and the availability of even better performing 24/96 cost-competitive commercial crossovers (excluding Behringer, of course), the cost of digital crossovers have become competitive with passives and are a real enabler for the full loudspeaker design avoiding much trial-and-error time.

One thing that I did learn was apparently how easy it is to be successful using multiple entry designs. Just do it: cut the holes (once you've calculated where they should be in Hornresp) and attach the woofers...and proceed like you know what you're doing. The results are spectacular.

But being a kit business isn't something for the weak willed, and can get to be a big pain. And making finished hi-fi stuff doesn't look at all like fun, seems like most of the work and expense goes to marketing at shows and in print.

I think that the gain is in helping others (living somewhat vicariously at the same time :grouphug:) Also, it may give you a little extra income to continue development of kits and to upgrade your own setup(s). I'd say you'd be one of the best go-to guys that exist for that sort of thing.

My current focus is the horn issue.


Paid Member
2004-10-07 6:05 am
I've heard all the commercial Danely Synergy speakers and the only one I'd consider for Hi-Fi is the SH50. Maybe the SH60. The SH50 is remarkably good.
Making something that good by DIY is going to be for advanced builders. Of course we have a few of those here. ;)
Cask05, what is the cost of the K402? Goggled just now and the Klipsch site shows the KPT-305-MB at $10k!! (though, with driver, and for that matter it shows that same price for EVERY pro speaker there?!? Glitch?).

Last search I did a while ago, though, had a used one for (I think) over $1.5k. I can spend a lot of time at a table saw for that!

I'm trying to nail down the diff between Synergy and Unity, not being a patent lawyer (I had to work through some patents of my own with a lawyer a few years back, but I don't feel at all confident I can surf well through the "claims" of patents). Is it only the crossover? Are the bevels in the mid ports protected?
Bill, I too am trying to grasp the refinements that went from Unity to Synergy. I'd say improved crossover tricks, as well as the port refinements ("frustrum").

For OP, I hope you'll share your search for your Unity or Synergy type horn. Unless you are willing to spend several thousand dollars per speaker, your only option is to build a DIY clone. There are many choices.

Before I get off on a tangent (often!), I would gladly share the links I've collected since researching Unity or Synergy.

While it is true that for an advanced, or even a moderately good, horn or waveguide, that quite good wood working skills and expensive equipment is required, all is not lost.

You can build them out of styrofoam :) just search for xrk971 (user) and read of his exploits. Even lower down the quality scale, save those few who modeled with cardboard boxes, is my own work. Probably essentially the same as foamcore, I often use plastic advertising signs ("coroplast") collected for free along the road side. For smaller drivers (which is 99% of a horn or waveguide) you probably don't even need any wood, just panels and glue of your choice.

I will briefly blow my own horn (so to speak!): my current set of Unity-like clones each one is made from 8 sheets (24x18") and one 24x24" (rear), making a 24" square front horn. The driver is the Typhany TC9 and the mids are a couple of old drivers similar to what were used in the Bose 901. I already had a miniDSP and amps so can EQ as needed. The sound is wonderful. Not bad for maybe $50 worth of parts per speaker.

With better quality materials, some testing, research, anyone could probably do even better. A main point: you can at least sample what Danley's invention offers, without even needing to cut a board or drive a screw :)

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Just had another look at the Unity/Synergy patents. No mention of the port bevels in the claims, so I guess that's ok. But the very first claim in the Synergy patent has me scratching my head:

I claim:
1. A system for reproducing sound, comprising:
a sound barrier de?ning a horn passageWay having a ?rst
end and a second open end;
at least one high frequency range driver at the ?rst end;
at least one loWer driver operating in a frequency range
loWer than the high frequency range driver;
the at least one high frequency range driver and the at least
one loWer driver mutually coupled to the horn passage
the at least one loWer driver having an upper frequency end
loWer than a frequency of a ?rst cancellation notch for
the at least one loWer driver.

I can't see how that is any different than the Unity. What am I missing?

Also the 4th claim (lower frequency driver mounted outside the horn, "communicated" through a passageway) is clearly shown in the Unity patent.

Soldermizer, I agree, it is rather amazing how even simpler lashups can sound using the idea. The first time I played sound through one I made I was floored (well beyond the usual "I built it!" advantage would be expected to give. I at best hoped it wouldn't just suck)
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Oops, I did not imply that xrk971's foamcore builds are low quality, quite highly skilled. I meant in cheaper cost and quality materials. I do claim, unfortunately, that you will find few DIY guys beyond myself, for the magic combination of cheap materials, low quality workmanship, and (usually) low-quality components :D

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