First try
I got the horns assembled and painted. Built some 5cu ft enclosures for the Lambda Apollo 15"ers (about 3'hx1.5'wx1.7'd). Mounted the woofer in the top front of the cabinet, no back yet or baffles, or dampening materials. Made a line level crossover - LR second order LP at 300hz- with a buffer in front. Hooked up the horns to the passive speaker level network that Nick shipped with the horns, and set the horns on top the boxes. Used a 5w/ch pp amp on the horn and 30w pp amps on the woofers. No balancing or optimization of any kind. Not even volume balancing top and bottom. And..., very promising. Dynamic? Oh, yes. Very clean and clear, even with no mods to the mid entry ports yet. This should be fun.
Sheldon
I got the horns assembled and painted. Built some 5cu ft enclosures for the Lambda Apollo 15"ers (about 3'hx1.5'wx1.7'd). Mounted the woofer in the top front of the cabinet, no back yet or baffles, or dampening materials. Made a line level crossover - LR second order LP at 300hz- with a buffer in front. Hooked up the horns to the passive speaker level network that Nick shipped with the horns, and set the horns on top the boxes. Used a 5w/ch pp amp on the horn and 30w pp amps on the woofers. No balancing or optimization of any kind. Not even volume balancing top and bottom. And..., very promising. Dynamic? Oh, yes. Very clean and clear, even with no mods to the mid entry ports yet. This should be fun.
Sheldon
Sheldon said:
Well, I finally got around to trying this. I cut some drinking straws into 3/4 inch pieces and placed a bundle of 6 in each hole. Eh, slight effect on smoothing the tweeter response. If I cover the holes with tape, the smoothing effect is much more pronounced. In both cases the measurements were taken on axis. Slightly off axis, the response is smoother (is that a word?) anyway and the difference is much less. Maybe this is why John said that the problem is not a big one. Anyway, got some carving and finishing to do.
Sheldon
I have read this thread twice now and Im realy intrested in this design.
Yesterday I bought some board to build a simple prototype, so that I can fool around with it and hopefully learn something about it.
Its seems to be a major advance in horndesign, but I dont se that many people building it or raving about it?!?! High efficiency, controlled dispertion and a pointsource behaviour all at once from a simple to build (no bent panels) horn is realy something!
Tomorow I will start building it.
I have some questions about it, and I hope someone can answer them. Info is a bit scarse on the net.
1, How would you do if you were to build a much larger 3 way, full range or 80 - 20000 hz version? Say something like 48 x 48 inch mouth and 46 inch deep or so. Could that work? Could such a large horn influence the responce in the treble???
2, How thick does the walls of the horn have to be? It seems like most people building it use 5/8 or 3/4 inch MDF. That seems a bit thin to me with that large panels?!? Are there any problems with panel resonances?
3, Could a 2, 3 or 4 inch compression driver be used and crossed over at a lower frequency to ease construction and allow for a deeper responce??? (and allow the use of 6½, 8 or 10 inch mid drivers?)
Johannes.
Yesterday I bought some board to build a simple prototype, so that I can fool around with it and hopefully learn something about it.
Its seems to be a major advance in horndesign, but I dont se that many people building it or raving about it?!?! High efficiency, controlled dispertion and a pointsource behaviour all at once from a simple to build (no bent panels) horn is realy something!
Tomorow I will start building it.
I have some questions about it, and I hope someone can answer them. Info is a bit scarse on the net.
1, How would you do if you were to build a much larger 3 way, full range or 80 - 20000 hz version? Say something like 48 x 48 inch mouth and 46 inch deep or so. Could that work? Could such a large horn influence the responce in the treble???
2, How thick does the walls of the horn have to be? It seems like most people building it use 5/8 or 3/4 inch MDF. That seems a bit thin to me with that large panels?!? Are there any problems with panel resonances?
3, Could a 2, 3 or 4 inch compression driver be used and crossed over at a lower frequency to ease construction and allow for a deeper responce??? (and allow the use of 6½, 8 or 10 inch mid drivers?)
Johannes.
My guess on why they're not many builders is that it's more complicated than individual horns and there are no software models available to diy'ers. The principles are layed out in the patent, but there is not a lot of practical info on actual constructions. Also, you'd have to figure out appropriate drivers and rear enclosures. Not impossible, but you've got to have some specialized knowledge. It's still new enough that those in the know appear reluctant to reveal their secrets - likely to protect some additional advantages over potential competition. I'd be pretty sure it ain't the diy'ers that they are worried about. But if the info is on a forum, anyone can find it.
1) Tom Danley's licensee does make a larger version.
http://www.servodrive.com/SPL-td1.html
From the pictures and descriptions, it appears to be pretty much the same configuration for the smaller drivers as what we have here, but extended and with larger drivers added. The mouth doesn't look square, so I'm sure that would require a little tweaking.
2) You can always go thicker, or add struts to stiffen the panels. I don't see a downside other than cost and weight.
3) Don't know about this one, but, in principle, I don't see why not. For a real answer, you're gonna have to hope one of the gurus chimes in.
I hope you try. I'd welcome the company. I'm still waiting for parts for the woofer assembly and building some additional amps. I'm strongly leaning towards taking John's advice and using something like the DEQX for crossover work. If nothing else, it seems like a much easier way to design and test, even if I end up with an analog line level crossover on the horn. I'm guessing it's more user friendly (at least for this user) than the computer card based equivalents.
Sheldon
1) Tom Danley's licensee does make a larger version.
http://www.servodrive.com/SPL-td1.html
From the pictures and descriptions, it appears to be pretty much the same configuration for the smaller drivers as what we have here, but extended and with larger drivers added. The mouth doesn't look square, so I'm sure that would require a little tweaking.
2) You can always go thicker, or add struts to stiffen the panels. I don't see a downside other than cost and weight.
3) Don't know about this one, but, in principle, I don't see why not. For a real answer, you're gonna have to hope one of the gurus chimes in.
I hope you try. I'd welcome the company. I'm still waiting for parts for the woofer assembly and building some additional amps. I'm strongly leaning towards taking John's advice and using something like the DEQX for crossover work. If nothing else, it seems like a much easier way to design and test, even if I end up with an analog line level crossover on the horn. I'm guessing it's more user friendly (at least for this user) than the computer card based equivalents.
Sheldon
Circlomanen said:
you're pushing this design to more esoteric lengths than most would attempt at first
get a working proto first... simple one
for a large horn like your'e talking about i would look into 1+ inch thick material... maybe double up to assurance
I wouldn't attempt a 3-way with this horn without quite a bit of experience
it's been done I believe though... 6-8" midbass, 4" midranges and horn driver
I researched this quite a bit before I decided against it
this design would greatly benefit from a fully active xover with phase adjustment and quite a bit of TA abilities
I sure as hell wouldn't try passives here until you work it out actively
again I wouldn't try a bigger compression driver until you work it out
model the horn in hornresp to figure out how low it can go... then test and test some more... then look into bigger throat stuff
I would start with a 2" horn, and 4 5" midranges and a 200 hz "HP" horn
Circlomanen said:
Try searching at Audio Asylum HiE forum for posts by Tom Danley as well. 'tomservo' is his moniker there, I think.
Besides the TD-1, etc., I built my own 2-way horn. See:
http://ldsg.snippets.org/HORNS/images/systems/unitystack.jpg
A bigger mouth would work, but as shown in my horn and the TD-1, it is not strictly necessary to make the design work. You would get better horn loading at low frequencies with the larger mouth and a longer horn, though. The highs should still be fine (compared to a smaller horn) as long as your midrange and bass entry holes are designed correctly. The tweeter response might change due to the horn having more control over the pattern to a lower frequency, though. I would only see that as a plus, though. You will already have to eq the tweeter to get flat response anyway.
Thick enough. How much is enough is up to you. ;>
There will always be panel resonances. Everything resonates - the question is how much, at what frequencies, etc. Being more practical, I did not notice any horrible problems with 3/4" material in the standard size horns I built (see my webpage for pictures of other ones).
Do note that shorter holes (along with the appropriate area) are usually more desirable than long holes, so panel thickness does start to become a tradeoff there. I think John Hancock discussed this a bit further back in the thread.
Yes. However larger diaphragm drivers usually have poor high frequency performance. Even if you use something that has output at 16khz, for example, it is mostly resonance. You have to go to beryllium to get past the usual limitations, and even there, a 3" dome will start to breakup above 15khz or so, iirc. One option that Tom has used are the BMS coaxial compression drivers, the 4592 and 4594, iirc. I think he said he built a unity with one of these covering either 500hz or 300hz and up, and used 8" or 10" drivers to cover the lower frequencies. The drivers are expensive, though. You are just trading ease of design and construction on your part for a more complicated, expensive compression driver.
John
Audiophilenoob said:
No, sorry if I was too cryptic. The Unity horn was made by Nick Mckinney when he had Lambda Acoustics. I bought the last pair. He sold them as a kit, unfinished, but complete with the mid drivers and passive crossover. I got some used TAD 2001's for the tweeter. So nothing much new to see there, other than I painted them.
I also have a 15" Lambda Apollo TDX to use for the mid-bass. I plan to mount that on a modified open baffle. Below that, literally and figuratively, I'll have a 12" Lambda TDX and two 15" pr's in a 21/2 cu ft. sealed box. I'll post some pics when I get closer to the end.
Sheldon
A picture.
I have just put together a prototyp of the horn. I mounted two cheap 4 inch caraudio drivers and a cap. It sounds horrible! But thats expected. I need two more midrange drivers and a compression driver for the high frequency, and a crossover. Its a lot of stuff left to do.
The horn with only two drivers could reproduce 200 to 1200 hz sinewaves at 100 dB without any audible distortion.It did have output down to 120 hz, and at 70 hz there was a LOT of port noice. Its always a start.
An externally hosted image should be here but it was not working when we last tested it.
I have just put together a prototyp of the horn. I mounted two cheap 4 inch caraudio drivers and a cap. It sounds horrible! But thats expected. I need two more midrange drivers and a compression driver for the high frequency, and a crossover. Its a lot of stuff left to do.
The horn with only two drivers could reproduce 200 to 1200 hz sinewaves at 100 dB without any audible distortion.It did have output down to 120 hz, and at 70 hz there was a LOT of port noice. Its always a start.
Re: A picture.
Is anyone still interested in doing a Unity? There's a thread on carsound.com that's reverse-engineering the Unity.
http://www.audiogroupforum.com/csforum/showthread.php?t=62789
Circlomanen said:
Is anyone still interested in doing a Unity? There's a thread on carsound.com that's reverse-engineering the Unity.
http://www.audiogroupforum.com/csforum/showthread.php?t=62789
Well, I may be totally nuts, but after eyeing them for years I finally pulled the trigger on the Yorkville U15's. After considering other options and deciding that I was looking at either continuing with open-ended experiments or else shelling out a very significant fraction of the U15's price in raw parts for something relatively 'safe', it seemed like the best option.
I expect to have to spend some time massaging them to make them suitable for home use, but I'm obviously hoping that the basic package is pretty close.
I expect to have to spend some time massaging them to make them suitable for home use, but I'm obviously hoping that the basic package is pretty close.
dwk123 said:
It will be interesting to see what requires massaging. Maybe cabinet resonances or just a different response profile for sound reinforcement vs. home use? There appear to be some new PC based crossover options, if you are pretty fluent with a computer (my dad called it a confuser). You can test and measure lots of stuff quickly, then convert to active or passive analog later if you prefer that.
One thing I recommend is to look into the foam as described on Earl Geddes's site and the carsound thread. On my Unity's I could pick up a slight horn resonance. My hearing tuned it out quickly and I'm pretty sensitive to it - I hear it in back horns - so it wasn't a big deal. But the foam eliminated it entirely. I also made sure that there were no physical bump or discontinuities at the junction of the driver and horn.
Sheldon
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