I believe the patent is still valid, but DSL hasn't been very litigious. Red Spade Audio sold a kit, and that didn't appear to be authorized. This forum has a sub posted that's literally a verbatim copy of the TH-SPUD.
Methinks they're too busy building Jericho horns for stadiums to worry about the DIY crowd building Synergy horns.
OK, I checked :
https://www.google.com/patents/CA2610999A1
If I'm reading this right, the Synergy Horn patent expires in 2020. I am not a lawyer so don't quote me on that.
https://www.google.com/patents/US6411718
HOWEVER, the Unity horn patent expired last month. On top of that, Sound Physics Labs is no more.
So, again, consult your lawyer, but it looks to me that you could make Unity horns without legal ramifications.
As I see it, there are two main differences between a Unity horn and a Synergy horn. And only one of those differences is physical.
IE, it seems like you should be able to make a Unity horn. (again, this is NOT legal advice, consult a lawyer.)
https://www.google.com/patents/CA2610999A1
If I'm reading this right, the Synergy Horn patent expires in 2020. I am not a lawyer so don't quote me on that.
https://www.google.com/patents/US6411718
HOWEVER, the Unity horn patent expired last month. On top of that, Sound Physics Labs is no more.
So, again, consult your lawyer, but it looks to me that you could make Unity horns without legal ramifications.
As I see it, there are two main differences between a Unity horn and a Synergy horn. And only one of those differences is physical.
IE, it seems like you should be able to make a Unity horn. (again, this is NOT legal advice, consult a lawyer.)
Patrick, what are the two differences you refer to? All I can see different is how things might be calculated (which would be damn hard to prove in court). What's the other?
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BTW, a very good reason for Synergizing a SEOS is to get the acoustical centers close enough. It's otherwise difficult to get midwoofers within or near a quarter wavelength of the usual 90x60 type horns, so there is vertical lobing and at frequencies where absorption is difficult to achieve with room treatment. A lot of people think of Synergy horn as just "wow, big horn!" but I think its main benefit is the polar consistency.
I'm getting horizontal directivity control below 400Hz using a synergized SEOS15 (via the addition of an array trick with a pair of spaced midwoofers). In smaller rooms, there isn't much point in directivity below that frequency (though vertical directivity to a usable frequency would be nice to have!). The major benefit of using a SEOS as a start like in the SmallSyns is you can then get some of the synergy benefits in a speaker that would be acceptable in most non-hot-rodders' homes! Wives do not love 30 inch horns usually.
----
BTW, a very good reason for Synergizing a SEOS is to get the acoustical centers close enough. It's otherwise difficult to get midwoofers within or near a quarter wavelength of the usual 90x60 type horns, so there is vertical lobing and at frequencies where absorption is difficult to achieve with room treatment. A lot of people think of Synergy horn as just "wow, big horn!" but I think its main benefit is the polar consistency.
I'm getting horizontal directivity control below 400Hz using a synergized SEOS15 (via the addition of an array trick with a pair of spaced midwoofers). In smaller rooms, there isn't much point in directivity below that frequency (though vertical directivity to a usable frequency would be nice to have!). The major benefit of using a SEOS as a start like in the SmallSyns is you can then get some of the synergy benefits in a speaker that would be acceptable in most non-hot-rodders' homes! Wives do not love 30 inch horns usually.
Renkus Heinz co-entrant horn (patent expired).
Newer versions only use one compression driver.
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There's a very specific way of doing the crossover that's part of the Synergy Horn 'secret sauce' and it's in the Synergy Horn patent, but not the Unity Horn patent.
That's the first part of the puzzle, and it's probably the greatest innovation of the Synergy Horn over the Unity Horn IMHO. I've listened to SH-50s and Lambda Unity Horns in the same room, and the SH-50 definitely sounds a *lot* different.
But that part of the puzzle has nothing to do with a flat pack.
The *physical* difference between a Unity horn and a Synergy horn is the midrange taps.
Very good points Bill. I've listened to the SH-50 and completely understand where both of you are coming from. My current speakers control directivity down to 900-1000 Hz (in the horizontal plane) with astonishingly flat directivity index up to 10khz. An octave below 900 Hz would be great but my waveguide is already 18 inches! So the next step is the Synergy. The SH-50 is exacting in its imaging in particular.
Best,
Anand.
That's the method that appeals to me.
The size limit can be ignored if you are willing to start with a basic horn, and extend the mouth to get whatever size you want. I've noted before that the PA horns Frangus already has, if extended, would be very similar to the K402.
I've tried this myself - using scrap timber for the rough shape of the extension and filler (lots of filler!) to get the transition and surface smooth. OK result, but a lot of work to get there. In hindsight, I wish I'd borrowed more ideas from the Book of XRK971
1) make quick mouth extensions by taping foamcore (or bendy ply, corflute, whatever) to the outside of the original horn
2) add a few layers of of fibreglass (or whatever) to the inside to get a smooth, continuous curve
3) paint / découpage / whatever for aesthetics
-this would be a lot lighter & faster than what I did, and allow for much bigger mouth extensions.
Step 2) could use paper mache, making this a feasible project for an apartment dweller.
Attachments
There are midrange taps in the Unity patent, but the innovation of using frustrums is in the Synergy horn patent.
It's a fairly small difference, but it improves the frequency response. I did a quick review of the Unity horn patent, and the frustrums aren't there:
https://www.google.com/patents/US6411718
A lawyer told me that the only thing that matters in a patent is the claims. The rest of the material merely provides context with which to clarify the claims. The differentiating synergy claims are:
1. crossover at/below the cancellation notch frequency
2. mid taps located where the circumference is less than a wavelength at crossover
3. mid taps located where the flare expansion rate is lower than where the HF enters
these are the guiding principles we all use to get point source behavior
the Unity patent says this re the mid tap location
"wherein respective ones of said pair of loudspeaker drivers are coupled to ....at a distance from said throat corresponding to the distance...to travel 1/4 wavelength"
Its much less precise language that overlaps with #1 above (to the delight of lawyers) but doesn't speak to the bullets 2 & 3 above. You could build a Unity horn and get lucky with where the mid ports fell, or not
But it really doesn't matter what it says in the patent, except in so far as it teaches us how to design a Synergy horn. Regardless of who might eventually win the suit, a small commercial effort is doomed simply by the threat of litigation. Such suits can cost millions in legal fees both to prosecute and defend, less if handled by internal legal staff, which the initiator is likely to have. A small company or an individual simply can't afford the risk.
Seems to me to be much safer to base the Synergy on an existing, commercially available waveguide.
1. crossover at/below the cancellation notch frequency
2. mid taps located where the circumference is less than a wavelength at crossover
3. mid taps located where the flare expansion rate is lower than where the HF enters
these are the guiding principles we all use to get point source behavior
the Unity patent says this re the mid tap location
"wherein respective ones of said pair of loudspeaker drivers are coupled to ....at a distance from said throat corresponding to the distance...to travel 1/4 wavelength"
Its much less precise language that overlaps with #1 above (to the delight of lawyers) but doesn't speak to the bullets 2 & 3 above. You could build a Unity horn and get lucky with where the mid ports fell, or not
But it really doesn't matter what it says in the patent, except in so far as it teaches us how to design a Synergy horn. Regardless of who might eventually win the suit, a small commercial effort is doomed simply by the threat of litigation. Such suits can cost millions in legal fees both to prosecute and defend, less if handled by internal legal staff, which the initiator is likely to have. A small company or an individual simply can't afford the risk.
Seems to me to be much safer to base the Synergy on an existing, commercially available waveguide.
Guess I misread the Unity patent, thought the frustrums were in there. But as mentioned, it's the Claims section only that is enforceable and the synergy patent mentions no frustrums in the claims.
Pre-existing Unity horns crossed over below the notch frequency, so that is certainly prior art (the coentrant horns would have been be pretty much inusable in general if the notch fell in the midrange passband)
Pre-existing Unity horns crossed over below the notch frequency, so that is certainly prior art (the coentrant horns would have been be pretty much inusable in general if the notch fell in the midrange passband)
Bill,
As I read it, if you use a digital crossover--none of the claims of the Synergy patent (8284976) can be effectively enforced for the basic horn/driver configuration.
I've read these two patents--Unity and Synergy--many times over a period of time, and I can't interpret the second one (DSL) in any way, shape or form as differing from the Unity patent (6411718): prior art overtakes all of the second patent's legal claims except the crossover discussion. That's it. And they didn't patent the crossover design in the claims.
Looking back over time, apparently Tom Danley left SPL under conditions that were not the best...meaning that the company was apparently folding and was laying off staff. So the Unity patent itself probably died with the company as part of its declared assets. So the 8284976 Synergy patent appears to be merely picking up the scraps from the basic design of 6411718 ("Unity Summation Aperture").
The second patent (DSL Synergy patent 8284976) took an extraordinary length of time from submission to grant--several years--indicating trouble at the USPTO. 6411718 isn't mentioned in the prior art section. (Smell Limburger cheese?)
But it's actually sad for Tom what happened, however. I've felt that pain myself having had essentially the same thing happen to me decades ago. I believe that Tom's follow-on patent for manifolding drivers together (Paraline?) is the one that's definitely making the money for DSL now. Bully on him. I hope they continue to prosper.
I believe that the DSL Synergy patent was meant to somehow protect DSL against the other big PA suppliers providing passive crossover loudspeakers for PA use in a Synergy configuration, and I believe that it's basically done its job in that respect - instilling FUD in its competitors to not do that. I also don't believe that these competitors would try to do a copy of the MEH (multiple entry horn) design anyway due to "NIH". You know how that works. JBL has something that begins to look like a "feeding trough" design now, but that's about as close as it gets. But as far as home audio goes, I don't believe that the DSL president is interested in the home consumer audio business (I don't blame him--it's very fickle.) I don't believe that DSL really cares about DIYers on diyAudio building their own.
BTW: there are now two K-402-MEHs operating. The other one is owned by another Klipsch forum member.
I'm listening to the first one as I type this playing The Yellow Jackets Time Squared multichannel SACD, which is unbelievable. Compared to Klipsch Jubilees playing on either side of it in my setup, the K-402-MEH is much more focused and displays an amazing presence and vocal clarity/intelligibility in the midbass (200-500 Hz) than does the Jubilee. It's MTF-related, I'm sure.
Chris
As I read it, if you use a digital crossover--none of the claims of the Synergy patent (8284976) can be effectively enforced for the basic horn/driver configuration.
I've read these two patents--Unity and Synergy--many times over a period of time, and I can't interpret the second one (DSL) in any way, shape or form as differing from the Unity patent (6411718): prior art overtakes all of the second patent's legal claims except the crossover discussion. That's it. And they didn't patent the crossover design in the claims.
Looking back over time, apparently Tom Danley left SPL under conditions that were not the best...meaning that the company was apparently folding and was laying off staff. So the Unity patent itself probably died with the company as part of its declared assets. So the 8284976 Synergy patent appears to be merely picking up the scraps from the basic design of 6411718 ("Unity Summation Aperture").
The second patent (DSL Synergy patent 8284976) took an extraordinary length of time from submission to grant--several years--indicating trouble at the USPTO. 6411718 isn't mentioned in the prior art section. (Smell Limburger cheese?)
But it's actually sad for Tom what happened, however. I've felt that pain myself having had essentially the same thing happen to me decades ago. I believe that Tom's follow-on patent for manifolding drivers together (Paraline?) is the one that's definitely making the money for DSL now. Bully on him. I hope they continue to prosper.
I believe that the DSL Synergy patent was meant to somehow protect DSL against the other big PA suppliers providing passive crossover loudspeakers for PA use in a Synergy configuration, and I believe that it's basically done its job in that respect - instilling FUD in its competitors to not do that. I also don't believe that these competitors would try to do a copy of the MEH (multiple entry horn) design anyway due to "NIH". You know how that works. JBL has something that begins to look like a "feeding trough" design now, but that's about as close as it gets. But as far as home audio goes, I don't believe that the DSL president is interested in the home consumer audio business (I don't blame him--it's very fickle.) I don't believe that DSL really cares about DIYers on diyAudio building their own.
BTW: there are now two K-402-MEHs operating. The other one is owned by another Klipsch forum member.
I'm listening to the first one as I type this playing The Yellow Jackets Time Squared multichannel SACD, which is unbelievable. Compared to Klipsch Jubilees playing on either side of it in my setup, the K-402-MEH is much more focused and displays an amazing presence and vocal clarity/intelligibility in the midbass (200-500 Hz) than does the Jubilee. It's MTF-related, I'm sure.
Chris
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Thanks Chris. I followed you on the other forums about your 402's and happy to hear your thoughts on this design also.
Pics or it didn't happen:
from here : https://community.klipsch.com/index.php?/topic/161404-a-k-402-based-full-range-multiple-entry-horn/
from here : https://community.klipsch.com/index.php?/topic/161404-a-k-402-based-full-range-multiple-entry-horn/
Very seasonal.
I'm not sure about the imaging with the tweeter position though ;-).
Best wishes.
Grant.
The K-510 horn with K-69-A compression driver that you see on the hearth was the midrange of my tri-amped JuBelle that was in the center a day before taking that shot (with a Beyma CP25 attached but out of view). I left that horn/driver stack sitting there thinking that I was going to tweak the new K-402-MEH center and replace back the JuBelle._______________________________________________________________________________________________ The K-402-MEH didn't move however and I simply dialed in the EQ and delays as-is. The rest--as they say--is history. It's been sitting there since January: I listen to it all day now, and can't bring myself to move it back in the garage. ____________________________________________________________ I'm building more so I can tweak those.____________________________________________________ Chris_____________________________________________________ P.S. the parsing out of CRs on edit really sucks now...Pano, where are you?
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