Welcome to engineering. The theories discussed in this thread are, as far as I know, the bleeding edge of waveguide theory. While they may not account for 100% of what's happening, the sims do match the measurements amazingly well.
The only "black art" here is in figuring out how to make physical prototypes of these massive horns. 😀
"opinion" is one thing, "response" is another and by that i mean i'm looking for a consensus by a greater majority in what the device does rather than go the way of designing to personal taste.
and there's another thing that cheezes my off in audio discussions the cop out of " you can't account for personal preference"...
and there's another thing that cheezes my off in audio discussions the cop out of " you can't account for personal preference"...
So back to reproduction vs. effect-machine?
There is 1 version for reproduction and an infinite number for effect preference...
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There is 1 version for reproduction and an infinite number for effect preference...
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What would be interesting to see is, what an theoretically optimal waveguide would look like, versus a non optimal at listening position, in room response!
Sort of the distortion figures in drivers as Geddes claim. "If good enough..."
Sort of the distortion figures in drivers as Geddes claim. "If good enough..."
Agree - many a profile and simulation has passed here. I think I might understand what is aimed for but I'm not sure why really. Why is a certain directivity sought after? What is it going to lead to? And why is that good? And for what room?
I don't recall seeing the full path of thinking... requirement (and why) -> result... just to understand which parameters a requirement specification should contain is not an easy task I suppose... then comes the parameters required values...
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I don't recall seeing the full path of thinking... requirement (and why) -> result... just to understand which parameters a requirement specification should contain is not an easy task I suppose... then comes the parameters required values...
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Turk, With all due respect and in my observation, you seem a little salty towards current waveguide approach. Can I ask if you've owned a good modern waveguide / CD combo and had it set up with proper EQ and such? I feel like for most who have heard or owns one, the state of affairs is pretty obvious, and exciting.
Like jcarothers said, the main problem right now is just building the darn things.
Like jcarothers said, the main problem right now is just building the darn things.
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Constant directivity is good for any room, any situation. Sound is same on a large listening area, reflections sound like direct sound as possible. Some might prefer a little narrower directivity some wider, even omni.
Seriously, anyone who is not quite sure what constant directivity means should think it through. Not sure why anyone would want anything else than constant directivity.
Besides smoothest constant directivity the simulations show almost no diffraction, I don't know if any other construction shows as little diffraction as the freestanding waveguides with rollback in this thread no matter what, OB, electrostats, all kinds of round corner speaker boxes seem to diffract more. It is kind of weird how the sound launches out in the simulations. Should be easy time for brain to hear the recording.
Doesn't mean other systems or waveguides sound bad, might be so that there is not much difference. Gotta remember these are just wave guides, they emit no sound on their own.
Seriously, anyone who is not quite sure what constant directivity means should think it through. Not sure why anyone would want anything else than constant directivity.
Besides smoothest constant directivity the simulations show almost no diffraction, I don't know if any other construction shows as little diffraction as the freestanding waveguides with rollback in this thread no matter what, OB, electrostats, all kinds of round corner speaker boxes seem to diffract more. It is kind of weird how the sound launches out in the simulations. Should be easy time for brain to hear the recording.
Doesn't mean other systems or waveguides sound bad, might be so that there is not much difference. Gotta remember these are just wave guides, they emit no sound on their own.
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"Doesn't mean other systems or waveguides sound bad, might be so that there is not much difference. Gotta remember these are just wave cuides, they emit no sound on their own."
@tmuikku: That is not what's claimed in this forum😉
I do understand the benefits, but where are the in room measurements...
@tmuikku: That is not what's claimed in this forum😉
I do understand the benefits, but where are the in room measurements...
One can EQ ideal constant directivity speaker to be flat or any else target curve, all around the room. The few measurements posted in this and "the practical" sister thread show measurements are close to the simulations so I'm not sure what you mean? Simulations in this thread are closest thing to ideal yet so expect room response be as good as it can be (currently) .
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As far as I remember, there are no measurements at listening position, and no comparison of other horns/waveguides. I'm maybe picky, but claims are made so confidentially these are perfect and those are bad, but without substance.
If I do research in my profession, I compare the systems to each other in the same real conditions!
If I do research in my profession, I compare the systems to each other in the same real conditions!
There's absolutely no point in doing steady state measurements at listening position. That's not what you hear in the end and that's the reason you won't see them in this thread - at least not made by me. That's not the kind of measurement useful to evaluate the quality of any sound source and you should know better.
I have done quite a few test samples many years ago, and some of the better performing samples are similar to the OS-SE, but I used the Lecleach expansion. It would be interesting to compare the two.
If you were able to provide the coordinates in a text form I could try to import them into Ath/ABEC and at least simulate. Axisymmetric, I assume.
I have simulated and measured before in one of the older horn threads. The CSD in the measurements did not look good enough for me. But probably using compression drivers, it would be a different story.
Yes, probably a transducer-related issues. There should be nothing observable in a CSD plot for a good waveguide, other than the resonances of a driver itself (and there are virtually always some, unfortunately). It's not always easy to separate the two and I found a plane wave tube quite handy for this.
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I think that the need for constant directivity (CD) is well understood, but let me give you my rational for a high DI.
As stated above, the DI should be smooth and flat (although some rise in DI may be acceptable to many, but very high DI rise yields the "head-in-a vice" situation which is not a great goal,) but what level should the DI be?
The higher the DI the greater will be the delay time between direct sound and the VER and reverberation. This will enhance the perception of image since image requires as clean a direct sound as is possible. This idea comes from studies which show that high DI improves intelligibility in reverberant spaces.
A low value of DI, CD or not, will enhance spaciousness, but sacrifice imaging. This may be an acceptable tradeoff for many, but not someone who prizes imaging.
I'd also like to point out a misunderstanding of CD that was discussed here earlier. CD does not mean a constant level as the angle moves off axis. In fact, IMO, this would not be a good thing. The level always falls off-axis, but with CD the frequency response stays constant even though the level falls. This turns out to be a great advantage in imaging since by correctly pointing the speakers we can have the level of the farther one increase as the nearer one decreases. This makes for a very wide "sweet-spot" which cannot be achieved any other way. To me a wide sweet-spot is far preferential to "Head-in-a-vise."
Without substance? Are you serious?
- This may not be perfect (maybe still a bit small) but then I would like to see a better waveguide. And this is a real measurement of a real (axisymmetric) device - the one that makes the most sense to compare:
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Very well explained gedlee. I say that my low DI speakers image similar to what I hear in the halls. Much more so than with some (short) appearances of standard box I have had in my room. I.e. there are not many sharp pinpointed things in the soundscape of an orchestra. I listen mostly with shut eyes, both in the halls and at home.
So no sacrifice for me, rather the opposite, more reproduction rather than "effect".
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So no sacrifice for me, rather the opposite, more reproduction rather than "effect".
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Are you also perfectly happy with the distance between the curves?
It's not a trick question - I really want to know.
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