Can you not mask the smaller room's acoustic signature? Use surrounds with appropriate delays and roll-offs?
Frank - The problem, I think but I maybe wrong, is a timing problem. It looks like you need a 10ms difference between the direct sound and the first lateral reflection (ignoring vertical and front wall reflections for now). I'm not sure how additional speakers would help with that.
I think there's been a debate somewhere in the forum about what the desirable time gap is between the direct sound and first lateral reflection and whether that is more important at certain frequencies than others. I've a vague recollection that Dr Geddes says that's what you need from c.800Hz up. I don't remember if there was an upper limit - 8-10kHz?
Stephen
I think there's been a debate somewhere in the forum about what the desirable time gap is between the direct sound and first lateral reflection and whether that is more important at certain frequencies than others. I've a vague recollection that Dr Geddes says that's what you need from c.800Hz up. I don't remember if there was an upper limit - 8-10kHz?
Stephen
When I listen to an orchestra from in a hall, I hear the size of the hall in small roons if they are well damped if I sit in the sweet spot or forward of it. It is better if it is in a larger room with high ceiling esp golden ratio, where ECT and RTA are optimised. No good with planar speakers though.
Yes but then, you are sitting in a position which masks the reflections of the listening room. How big is that sweet spot?
Quote: Originally Posted by FrankWW
Can you not mask the smaller room's acoustic signature? Use surrounds with appropriate delays and roll-offs?
Quote: Originally Posted by FrankWW
Can you not mask the smaller room's acoustic signature? Use surrounds with appropriate delays and roll-offs?
I've got a room that is 50% glass and brick, 50% wood for walls. No problems with imaging detail and spaciousness recovery using omnidirectional speakers. This works with speakers both close and far from highly reflective walls.
Ahhh the omnihorn (-: Must a horn we are speaking only of horns here right? I thought of a (possibly) new way to do that right but I am still researching. Brick is pretty good diffuser BTW that sounds like a good room.
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What kind of cracks me up about this is that there is no need to trade response smoothness OR distortion (e.g. diaphragm loading) in order to gain improved wavefront propogation.
When I see some people taking that position, it appears to me to be a missed-assessment on their part. I do see some people say they would take a hit in response smoothness and other factors in order to improve HOM. But that is not necessary, at least, not from what I've seen in other disciplines.
In the fields of optics, ultrasonics, microwave and sonar, the elliptic cylindrical and oblate spheroidal shapes are popular, and have been for some time prior to our adoption of them in acoustics. To be very honest, I probably wouldn't have been swayed by any of these HOM arguments if I didn't see corroboration in other disciplines. But when I started studing this flare profile (used in OS and EC horns, the hyperboloid that is tangent to an elliptic cylinder or oblate spheroid shown below), I found that it was being used in other disciplines specifically because of the way it acted with respect to high-order modes. However, in those fields, in so many papers written on the subject, they do not focus solely on HOM in exclusion of other attributes, like some people in audio do. So it is my belief that some people, who have been enamoured with this shape for audio horns, have missed the forest for the trees.
You can make a horn with the profile above that provides fairly good acoustic loading. So to chose dimensions that fail to do so is short-sided, in my opinion. That's probably my biggest beef with some waveguide proponents. They seem to want to plot that flare shape, make a horn that looks "pretty" with it, almost a seat of the pants thing. They add an arbitrary radius at the mouth, hoping to smooth out mouth diffraction and call it good. They assume that as long as it has that shape, all is well. But the result is they've really generated an arbitrary profile, and many of them have excessive response ripple. Of course, when they see that in measurements, they tack on some response shaping circuits, notch filters and other modifiers, and take the position it's not an issue. But to me, it is an unneccesary oversight, and I think performance suffers. Actually, I don't think that - I can clearly see it in the measurements.
Totally agree Wayne P. You apparently saw no reason to reinvent the wheel and you did not. Everything that I think I've leaned points to conventional horn speakers being a done deal and size being the trade off period. I see no drawbacks in deep conical horns either, loading the driver at low end is a winner, lower crossover a winner. I do however see great advantages in eliminating the tweeter and xover if possible. On the other hand Tom Danleys speakers may in fact be a whole nother beast. As far as I can see, regarding conventional horns, this is a silly game that ended in the 30s,
I think if I sold a speaker I would call it " The Big Azz Horn Speaker" and be done with it. Any size you want as long as its big with a big horn.(-:
On the We555 subject. What is different about this 2" aluminum throat driver? I find my old Peavey 22a units to be extremely EQ-able up to well above 17k seriously working well from 500hz to that range. For that matter other than the phase plug what are the real differences in any 2" aluminum driver. I know plenty has to do with the narrow throat giving me more headroom on this particular horn, but does that mean that a lot of similar 2" aluminum drivers would also work on this horn, even though they are rarely rated down to 500hz as the Peaveys are? I am thinking its more of a de-rating CYA sort of thing for PA use, and perhaps most would make it there in home or studio use?
On the We555 subject. What is different about this 2" aluminum throat driver? I find my old Peavey 22a units to be extremely EQ-able up to well above 17k seriously working well from 500hz to that range. For that matter other than the phase plug what are the real differences in any 2" aluminum driver. I know plenty has to do with the narrow throat giving me more headroom on this particular horn, but does that mean that a lot of similar 2" aluminum drivers would also work on this horn, even though they are rarely rated down to 500hz as the Peaveys are? I am thinking its more of a de-rating CYA sort of thing for PA use, and perhaps most would make it there in home or studio use?
As simple as it seems EGs idea about the throat radius is great, I am assuming the general idea works in any horn or am I wrong? I read it as "transition the driver to the horn in the smoothest most economical way possible, no sharp angles" No way that can be wrong unless you are designing something based on retraction. Well that brings this up: This sort of bothers me because I still see phase plugs as sort of diffraction devices. EG patiently tried to set me straight, I didn't quite get there.
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Not really a good one. Mostly forums where unokwledge people or those with vested interests have "captured the flag" and chasen away the few that trully have good knowledge about psycoacoustics.
But don't worry, you can contact me. Yup, a self exclaimed expert on small room acoustics.
Just don't waste my time with subjective nonsense and too much listening. Have your mic and measuring software ready. We go by the book!Yes but then, you are sitting in a position which masks the reflections of the listening room. How big is that sweet spot?
Quote: Originally Posted by FrankWW
Can you not mask the smaller room's acoustic signature? Use surrounds with appropriate delays and roll-offs?
Yeah, the sweet spot on my DHT system is small (2 ft) but I can adjust the tow in out a bit. But being in a small room, it does not need a large sweet spot.
More like earphones in a seat really. It is my 2nd running system. The first is a large high ceiling room. Quad ELS do not work in a small room due to planar sound and figure of eight radiation.
What kind of cracks me up about this is that there is no need to trade response smoothness OR distortion (e.g. diaphragm loading) in order to gain improved wavefront propogation.
When I see some people taking that position, it appears to me to be a missed-assessment on their part. I do see some people say they would take a hit in response smoothness and other factors in order to improve HOM. But that is not necessary, at least, not from what I've seen in other disciplines.
In the fields of optics, ultrasonics, microwave and sonar, the elliptic cylindrical and oblate spheroidal shapes are popular, and have been for some time prior to our adoption of them in acoustics. To be very honest, I probably wouldn't have been swayed by any of these HOM arguments if I didn't see corroboration in other disciplines. But when I started studing this flare profile (used in OS and EC horns, the hyperboloid that is tangent to an elliptic cylinder or oblate spheroid shown below), I found that it was being used in other disciplines specifically because of the way it acted with respect to high-order modes. However, in those fields, in so many papers written on the subject, they do not focus solely on HOM in exclusion of other attributes, like some people in audio do. So it is my belief that some people, who have been enamoured with this shape for audio horns, have missed the forest for the trees.
You can make a horn with the profile above that provides fairly good acoustic loading. So to chose dimensions that fail to do so is short-sided, in my opinion. That's probably my biggest beef with some waveguide proponents. They seem to want to plot that flare shape, make a horn that looks "pretty" with it, almost a seat of the pants thing. They add an arbitrary radius at the mouth, hoping to smooth out mouth diffraction and call it good. They assume that as long as it has that shape, all is well. But the result is they've really generated an arbitrary profile, and many of them have excessive response ripple. Of course, when they see that in measurements, they tack on some response shaping circuits, notch filters and other modifiers, and take the position it's not an issue. But to me, it is an unneccesary oversight, and I think performance suffers. Actually, I don't think that - I can clearly see it in the measurements.
Trouble is the math has to be accurate from the phase plug( or before that) to the roll off around the flare opening. and then maybe minor tweeks that are not calculated. But how do you do that with any real vision of what your doing.
By the way, nobody on this thread has mentioned surface texture as a functional surface for at least HOM. We know about low density filling the flare or skirting the flare with sponge. Is there any useful reports on the effectiveness of these that you could tell us about.
That sounds pretty honest actually (-: I know where the "traps" are.
Not really a good one. Mostly forums where unokwledge people or those with vested interests have "captured the flag" and chasen away the few that trully have good knowledge about psycoacoustics.
But don't worry, you can contact me. Yup, a self exclaimed expert on small room acoustics.
Someone mentioned texturing. Probably some real stuff going on there. Light felt at throat of horn where walls are parallel makes an audible difference that can be measured in fr. High frequency resonances from the tiny "room" created by parallel walls in horn throat being damped? Sounds HOMish.
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