Brett said:
Of course. Info may be a bit sporadic, though
Sheldon said:
I'm hoping it's along these lines. I 'know' the cab is a bit underdamped and need some fill, and it looks like the cabinet edges could use some felt/foam. The mouth termination doesn't look horrible, but it's not up to what Geddes would consider acceptable; that would be more significant work though.
My 'long term' plans are fully active with DSP xovers. I was a beta tester for Jan's Allocator which may work, although previously I used BruteFIR and that my actually be a better fit for this project. We'll see how that goes.
Sealing the cab is one big experiment I plan to do as well. The 50Hz cutoff of the existing vented cab is a bit higher than I'd like, although we'll see how it works in practice. Sealing the cab and applying some boost to get ~35Hz extension seems entirely feasible since the driver (If it's the one I think it is) has decent excursion and the power requirements aren't horrible. This may prove to be a bad idea, but it seems worth looking at.
Yeah - I saw that and as I said over there "you stole my idea"
. I was already planning that, but it's great to hear you already tried it. Shelling out $200 for foam may seem a bit daft, but having heard Earls speakers at RMAF, there's no question there is some substance to what he's doing.
dwk123 said:
Greets!
Wise decision IMO. After doing a bit of theorizing and drawing it full scale since I don't have a clue how to do it empirically with math, I concluded that putting the drivers at 1/4 WL was too far from the throat (at least when I use the standard 1130 ft/sec SoS) and that the centerline of the vent holes needed to be on the same plane as the driver's acoustic center, making it a far more complex juggling act of WG dims/driver specs than just looking at one and TD's description (which he notes), so without the proper test gear, etc., to find acoustic centers, etc., and the patience to find the right specs to get optimum size vents, the odds of approaching 'Unity'
were slim and none without a lot of expensive digital EQ and accepting a much lower mids efficiency.That said, I believe that even a crude approximation will be ~equal/superior to a typical multi-way horn system with its acoustically huge spread in the XO BW since my own bent baffle layouts sounded sujectively better than a typical flat baffle, but with only an RTA I had no way to dial it in 100%, though with the low and/or high XO points I used it probably wasn't a big deal. I mean look at an Altec 604 studio monitor driver, it's not time aligned, has some interesting reflections and polar response, etc., and a textbook Butterworth 2nd order XO at 1 k- 1.6 k Hz (depending on model) stuck in a large BR, yet still sounds better overall once properly EQ'd flat than many 'optimized' multi-way speakers.
GM
dwk123 said:Yeah - I saw that and as I said over there "you stole my idea"
Sounds like you've got a reasonable plan of attack. Oops, right, I forgot that you had mentioned the foam on the carsound site. As I said over there, I've got some scraps left over. May not be asthetically ideal for a permanent install, but would work fine for testing. If it's ok with Earl I'd be willing to send you some.
I'm curious about Earl's speakers. Sounds like you liked them. I occasionally check out the AA forum and it looks like Earl was driven off. A lot of those guys were criticising the speakers; maybe because they didn't like Earl? Had any of them actually heard them? I know Earl was not the most tactful guy in the word, but I never picked up any personal attacks in his posts. Plenty, though, in his detractor's. When I glance over the forum, there are a few people who, regardless the topic, if I see that they have posted I will read the thread. Earl was one of them, so is Tom Danley. Something to do with the odds of getting real information.
Sheldon
GM said:
Greets!
Wise decision IMO. After doing a bit of theorizing and drawing it full scale since I don't have a clue how to do it empirically with math, I concluded that putting the drivers at 1/4 WL was too far from the throat (at least when I use the standard 1130 ft/sec SoS) and that the centerline of the vent holes needed to be on the same plane as the driver's acoustic center, making it a far more complex juggling act of WG dims/driver specs than just looking at one and TD's description (which he notes), so without the proper test gear, etc., to find acoustic centers, etc., and the patience to find the right specs to get optimum size vents, the odds of approaching 'Unity'
GM
It is a tricky one. I tried some PC based measure/design programs and finally gave up in frustration at how much time I was spending on learning the software vs. generating useful results. This was with the goal of making an active analog crossover for the horn as well as for the horn/woofer crossover. I ended up getting the DEQX. It's not trivial to learn well, but it's much easier than the others.
As I calculate it, for a crossover around 1200 Hz, the 1/4 wavelength would be about 7 cm. That's about how far the entry holes are from the horn apex. When I measure with the DEQX I get the mids about 0.4ms before the tweeter. That translates to about 14 cm. Well, that is closer to the distance from the entry holes to maybe the diaphram of the TAD 2001. Don't know how the distance from the mid cone to entry hole enters into this, but it's 2-3cm. So, understanding of where acoustic centers are is lacking on my part. I had a copy of Danley's patent, but can't locate it at the moment. That may shed some light on it.
Anyway, now I just measure and let the DEQX do the time alignment. With a tool like this, or the PC based systems, it is not to hard to develop some active analog filters and take the computer out of the system for normal use. I may do that at some point, but since I also use the DEQX for room correction too it's not a high priority.
Sheldon
JoshK said:
Seems like you could. Also, at around $500 per driver ( if I have that right), it's not that steep. The one advantage of the Unity is that multiple drivers and a physical bandpass on the mids makes for very low distortion. I don't know if the BMS could match that on a constant directivity horn, but if it sounds good, it is.
Sheldon
dwk123 said:
I installed 2 pair of these in a Great House in Alert Bay
http://yorkville.com/default.asp?p_id=127
An externally hosted image should be here but it was not working when we last tested it.
At that point i decided that if i wanted to play with Unitys getting a pair myself would be the most sensible approach.
The designer is very ameniable to helping the diyer modify, teak, multi-amp, etc.
dave
JoshK said:
Depends on what you mean. The BMS was the other option that I was seriously considering, so here's my take.
If you're mainly after the ability to cover ~300Hz on up from a single horn, then the BMS can probably fit the bill. The practical problem is that there aren't any suitable horns/waveguides available off the shelf. The 18Sound XT1464 comes close, but
a) may not go low enough - they only spec it down to 800; 600 or a bit lower may be possible, but I doubt 300 is realistic
b) doesn't seem to be readily available in north america.
Sure, you can make your own, but having done some of that in my Unity prototypes, it's not something I'm going to rely on for a predictable schedule.
The aspect of the Unity that it won't do by default is the phase tracking due to the acoustic time alignment. This is probably a moot point if you use a DSP xover that has delay, though.
As Sheldon pointed out as well, the Unity will probably have lower distortion in the 300-1kHz region due to the bandpass and acoustic makeup, but I'm not sure this is really a factor at home listening levels.
planet10 said:
Cool! I saw that on the Yorkville site - didn't have any idea you were involved. How did it sound?
I still have some level of interest in continuing my prototypes for educational reasons, but obviously my shelling out $$$ indicates that I agree - if what you want is a working unit that can be listened to and played with, this is the way to go.
Yeah - Todd has posted on AA occasionally, and I used that link to send him email this morning. He got back to me in a couple hours, and was very approachable. Can't argue with that kind of attitude.
Sheldon said:
For the most part, yes. I only listened briefly, and with material I wasn't familiar with. The good aspect is that they disappeared - his extensive diffraction control really seems to work, and the speakers themselves had no real signature I could pick up.
The not so good is that they were a bit flat and unexciting. As is well documented, he was using $200 of Costo electronics to drive them which might be part of the problem. I'm also open to the idea that what I was hearing was the lack of artifacts and problems, but I didn't listen long enough to begin to form an opinion on that.
Yeah, same thing happened on the Bass List with Earl. I think it's largely a reaction to his rather brusque impersonal/academic manner and his complete lack of willingness to accept personal/anectodal evidence in discussions. I can understand much of this, but I can also see how it ruffles peoples feathers. This is even worse when Earl attacks things that are 'beliefs' for some folks.
The wierd thing is that I found him completely approachable and personable when I talked to him at RMAF.
My audio perspective/philosophy is largely formed by Geddes and Danley as well, and although I'm still a relative neophyte, the more I understand about what they're getting at, the less I find myself in sync with mainstream audiophile-dom. Although, I guess buying PA cabinets for my home speakers pretty much proves that.
dwk123 said:
Really good when consideration is given to the fact that it is mono, mounted in a "barn" with very reflective walls & seats, and a sand floor, and driven by a 200W commercial mono amp. It certainly more than satisfied everyone as far as the design goals went -- for people to be able to hear what the Elders were saying.
dave
dwk123 said:
It's hard to know what exactly you hear from a simple description. Just the nature of the beast. But "flat and unexciting" may have some truth to it. I've played around some with amps, speakers and with the Unity's. It's been my experience (limited to be sure, especially as compared to many people here), that what I perceive initially as "exciting" eventually annoys me. When I bought my first hign end system, I listened to a bunch of stuff. One of the SE amps had an almost spooky effect with female voices, which was cool. I can see why some like that ingredient. But I found myself going back to systems that were flat by comparison, but tonally pure. I do like the soundstage effect, so that's what I ended up with - a system that provided good spatial effects, but nothing "exciting", and no harshness. A matter of taste, for sure.
That's also what I find myself going for as I tweak the Unity's. Except, that I'm also getting expanded dynamics too.
dwk123 said:
That's an interesting way of putting it. Of course, I think Earl is of the opinion that he is not attacking anything, but rather, defending the imperical method. Problem is, he's not aware how important the romantic side of this is to perception and participation of many in the hobby. Our world today exemplifies how hard it is for true believers on opposite sides to communicate with one another. Hey, at least it's only audio and we all live to tell about it.
Sheldon
Sheldon said:
Yes - that's more or less what I was trying to get across. I have no problem believing that the Summa's may simply have been accurately reproducing what they were fed. I didn't really have enough time to come to a solid conclusion though, since I showed up late on Sunday as he was getting ready to pack up.
Tonal balance is easy enough to fix with your DEXQ or the VST/Allocator/SIR setup I'm planning to use. The other stuff isn't, and that's where the Summas were good, and I'm hoping that the Unities can equal that.
Absolutely - I didn't mean to imply differently. Earl is (generally) pretty careful about presenting pretty academic/objective arguments based either on math or on direct experimental evidence. However, when someone says "I like A because id does technical factor X better than B", and Earl basically says 'you are wrong, technical factor X is irrelevent', it doesn' t go over well.
As I said, this is why I was slightly surprised that he was so personable - he rubbed so many people the wrong way that I was expecting someone a bit more gruff. I quite enjoyed talking to him.
The freight company says they should be here tomorrow, but of course I'm heading out of town for the weekend :-(. I'll certainly followup after I've had a look and first listen.
GM said:
Greets!
Wise decision IMO. After doing a bit of theorizing and drawing it full scale since I don't have a clue how to do it empirically with math, I concluded that putting the drivers at 1/4 WL was too far from the throat (at least when I use the standard 1130 ft/sec SoS) and that the centerline of the vent holes needed to be on the same plane as the driver's acoustic center, making it a far more complex juggling act of WG dims/driver specs than just looking at one and TD's description (which he notes), so without the proper test gear, etc., to find acoustic centers, etc., and the patience to find the right specs to get optimum size vents, the odds of approaching 'Unity'
It's funny, I traded email with Todd Micheal (designer of the U15), and he more or less said the same things - that the balancing act between driver parameters, horn flare, xover etc was such that doing it without a full TEF setup was futile. And I get the impression that this is even with custom drivers - apparently the U15 mid xover is rather complex.
I find it interesting that John Sheerin who clearly understands these things better than any "diyer" I know of has shelved his Unity experiments despite the advantages.
I also agree with your final point - that us duffers can get something that works, but only with the help of digital eq to compensate for the driver mismatch (Since there is obviously not a decent off-the-shelf mid). My RS52-based prototype was really pretty amazing, but I needed a ton of eq, efficiency wan't that great, and it required a complex 4-way system setup.
dwk123 said:
You mentioned one element that could be important, and that is amplification. Earl may be of the school the all amps that measure the same, sound the same. On a gross level, that might be true. But most aren't measured with speakers, so I don't find it hard to believe that typical measurements don't cover all the issues that we can perceive.
dwk123 said:
I thought the choice of words was interesting, not as a reflection on your position, but because it did capture the apparent feeling of those who's arguments Earl took issue with. I think your statement above is pretty accurate.
It will be interesting to see what you find on the Yorkville's. John Hancock recommended that I buy them rather than try it on my own. I ended up buying Nick Mckinney's last pair (think he saved one other pair for himself). That turned out to be an interesting experience. Woulda got there faster had I followed John's advice, but while waiting, I made a bunch of amps. I've learned a lot in the process. When I finish the RIAA amp and a CD transport, the entire system, with the exception of the DEQX, will be DIY.
Sheldon
He invited me to his home and I got to spend a few hours listening to both of his systems, one a two channel the other a HT setup. He was a very pleasant guy and nice to talk with but he did have strong opinions as most of us do.
We talked a little about some of his current research efforts, because I studied statistics and applied mathematics so I practice so of the techniques he was using.
We talked a little about some of his current research efforts, because I studied statistics and applied mathematics so I practice so of the techniques he was using.
I gave up working on my unity because of two things:
-Conical horns don't have the 'snap' of a good horn system, ime.
-I couldn't find a good midrange, or even a cheap midrange, that had the specs I wanted.
The snap thing is based on some experiments that aren't done yet is kind of a subjective thing, but basically I want to try another fullrange horn system with non-conical horns. Actually I'm working on one at the moment.
The midrange thing is what really got me though - I don't want to use crappy drivers anymore. What's the point? It's the same amount of work to build a pretty complicated enclosure and do all the design work. But by using cheasy midranges, I just nocked the quality of the entire system down a notch. Not that I could find any drivers with the parameters I wanted anyway. So I designed my own driver, but then I moved (three times), and in the two years since I started that, I've had a million other ideas I want to try and the unity driver got put way on the back burner. You guys know how that goes. Maybe one of these days...
-Conical horns don't have the 'snap' of a good horn system, ime.
-I couldn't find a good midrange, or even a cheap midrange, that had the specs I wanted.
The snap thing is based on some experiments that aren't done yet is kind of a subjective thing, but basically I want to try another fullrange horn system with non-conical horns. Actually I'm working on one at the moment.
The midrange thing is what really got me though - I don't want to use crappy drivers anymore. What's the point? It's the same amount of work to build a pretty complicated enclosure and do all the design work. But by using cheasy midranges, I just nocked the quality of the entire system down a notch. Not that I could find any drivers with the parameters I wanted anyway. So I designed my own driver, but then I moved (three times), and in the two years since I started that, I've had a million other ideas I want to try and the unity driver got put way on the back burner. You guys know how that goes. Maybe one of these days...
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