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#1
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Baffle edge diffraction model, comments?
Hi all!
I have spent some time trying to understand how to model edge diffraction of a loudspeaker baffle. After some reading I came up with the following model: At a point on the baffle a point source is placed. A second point source will appear due to mirroring. At the edge additional sources appear. Net effect is two point sources and one line source along the edge of the baffle. I have quantized the line sources, to the default number 72 or one source every 5 degrees. Each of these 72 sources have an amplitude of -1/72 of the first point source, and a delay corresponding to the distance between the point source and the edge. I go around one turn to add all (line) point sources, and finally add them with the original point source and its mirror. From this fairly simple model I can calculate the "baffle step" effect for most baffle shapes. The results so far seems good, I have compared them with real measurements at http://www.linkwitzlab.com/diffraction.htm and also with some measurements of a collegue of mine. So far I have only simulated radiation straight ahead of the baffle, and I have also assumed that the speaker is a point source, which of course is an approximation. Furthermore, the edge reflections are assumed to have the same amplitude (scaled by the angle) as the first source. The program is available at: http://www.tolvan.com/diffract.exe If the simulation is correct, it should be very useful for designing the baffle of speakers, and also the placement of the speakers on the baffle. The user interface is so far a bit akward, my apologies. I am particularly interested in knowing if anyone has done more measurements that I could compare with, but any comments on the model/program are welcome! (I guarantee that there is no spyware/adware etc included in the program, and I use updated anti-virus software and have a well-working firewall, so the program should be safe.) |
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#2
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Baffle edge diffraction model, comments?
Svante wrote:
The program is available at: http://www.tolvan.com/diffract.exe Easy to crash if providing unexpected input, say a negative number of directions. Software that does not check for and discard unexpected input is vulnerable to buffer overflow. Not that that concern at all applies, I am not saying that this software is a security risk, but has been known and described in programming and software testing literature at least since 1979 that software must know how to handle also unexpected input. It should certainly not permit it via hitting a gadget with a mouse .... My point is not to critize you, it is trivial software and it doesn't matter, but to make it obvious how many precautions "safe code" requires and thus how much there still is to fix in "software as we know it" .... be it debian or mikerowesoft under new ownership. Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
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#3
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Baffle edge diffraction model, comments?
Svante wrote:
The program is available at: http://www.tolvan.com/diffract.exe Easy to crash if providing unexpected input, say a negative number of directions. Software that does not check for and discard unexpected input is vulnerable to buffer overflow. Not that that concern at all applies, I am not saying that this software is a security risk, but has been known and described in programming and software testing literature at least since 1979 that software must know how to handle also unexpected input. It should certainly not permit it via hitting a gadget with a mouse .... My point is not to critize you, it is trivial software and it doesn't matter, but to make it obvious how many precautions "safe code" requires and thus how much there still is to fix in "software as we know it" .... be it debian or mikerowesoft under new ownership. Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
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#4
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Baffle edge diffraction model, comments?
Svante wrote:
The program is available at: http://www.tolvan.com/diffract.exe Easy to crash if providing unexpected input, say a negative number of directions. Software that does not check for and discard unexpected input is vulnerable to buffer overflow. Not that that concern at all applies, I am not saying that this software is a security risk, but has been known and described in programming and software testing literature at least since 1979 that software must know how to handle also unexpected input. It should certainly not permit it via hitting a gadget with a mouse .... My point is not to critize you, it is trivial software and it doesn't matter, but to make it obvious how many precautions "safe code" requires and thus how much there still is to fix in "software as we know it" .... be it debian or mikerowesoft under new ownership. Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
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#5
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Baffle edge diffraction model, comments?
Svante wrote:
The program is available at: http://www.tolvan.com/diffract.exe Easy to crash if providing unexpected input, say a negative number of directions. Software that does not check for and discard unexpected input is vulnerable to buffer overflow. Not that that concern at all applies, I am not saying that this software is a security risk, but has been known and described in programming and software testing literature at least since 1979 that software must know how to handle also unexpected input. It should certainly not permit it via hitting a gadget with a mouse .... My point is not to critize you, it is trivial software and it doesn't matter, but to make it obvious how many precautions "safe code" requires and thus how much there still is to fix in "software as we know it" .... be it debian or mikerowesoft under new ownership. Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
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#6
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Baffle edge diffraction model, comments?
Svante wrote:
I am particularly interested in knowing if anyone has done more measurements that I could compare with, but any comments on the model/program are welcome! I love it and it fits the measurements I have of my System8 small reference monitor as I recall them. Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
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#7
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Baffle edge diffraction model, comments?
Svante wrote:
I am particularly interested in knowing if anyone has done more measurements that I could compare with, but any comments on the model/program are welcome! I love it and it fits the measurements I have of my System8 small reference monitor as I recall them. Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
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#8
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Baffle edge diffraction model, comments?
Svante wrote:
I am particularly interested in knowing if anyone has done more measurements that I could compare with, but any comments on the model/program are welcome! I love it and it fits the measurements I have of my System8 small reference monitor as I recall them. Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
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#9
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Baffle edge diffraction model, comments?
Svante wrote:
I am particularly interested in knowing if anyone has done more measurements that I could compare with, but any comments on the model/program are welcome! I love it and it fits the measurements I have of my System8 small reference monitor as I recall them. Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
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#10
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Baffle edge diffraction model, comments?
Peter Larsen wrote in message ...
Svante wrote: The program is available at: http://www.tolvan.com/diffract.exe Easy to crash if providing unexpected input, say a negative number of directions. Software that does not check for and discard unexpected input is vulnerable to buffer overflow. Not that that concern at all applies, I am not saying that this software is a security risk, but has been known and described in programming and software testing literature at least since 1979 that software must know how to handle also unexpected input. It should certainly not permit it via hitting a gadget with a mouse .... :-). No, of course this program is not intended for the "market". It just demonstrates my model and can easily be made to crash. I added the last lines because nowadays you can hardly find any free software (good or bad) that comes without ad/spyware or so. I simply declared my intentions and a little about the precautions I had taken to not spread viruses etc. My point is not to critize you, it is trivial software and it doesn't matter, but to make it obvious how many precautions "safe code" requires and thus how much there still is to fix in "software as we know it" .... be it debian or mikerowesoft under new ownership. Yes, agree. I do beleive, though that the code is safe, in terms of "hackability", even though it is crashable. |
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#11
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Baffle edge diffraction model, comments?
Peter Larsen wrote in message ...
Svante wrote: The program is available at: http://www.tolvan.com/diffract.exe Easy to crash if providing unexpected input, say a negative number of directions. Software that does not check for and discard unexpected input is vulnerable to buffer overflow. Not that that concern at all applies, I am not saying that this software is a security risk, but has been known and described in programming and software testing literature at least since 1979 that software must know how to handle also unexpected input. It should certainly not permit it via hitting a gadget with a mouse .... :-). No, of course this program is not intended for the "market". It just demonstrates my model and can easily be made to crash. I added the last lines because nowadays you can hardly find any free software (good or bad) that comes without ad/spyware or so. I simply declared my intentions and a little about the precautions I had taken to not spread viruses etc. My point is not to critize you, it is trivial software and it doesn't matter, but to make it obvious how many precautions "safe code" requires and thus how much there still is to fix in "software as we know it" .... be it debian or mikerowesoft under new ownership. Yes, agree. I do beleive, though that the code is safe, in terms of "hackability", even though it is crashable. |
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#12
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Baffle edge diffraction model, comments?
Peter Larsen wrote in message ...
Svante wrote: The program is available at: http://www.tolvan.com/diffract.exe Easy to crash if providing unexpected input, say a negative number of directions. Software that does not check for and discard unexpected input is vulnerable to buffer overflow. Not that that concern at all applies, I am not saying that this software is a security risk, but has been known and described in programming and software testing literature at least since 1979 that software must know how to handle also unexpected input. It should certainly not permit it via hitting a gadget with a mouse .... :-). No, of course this program is not intended for the "market". It just demonstrates my model and can easily be made to crash. I added the last lines because nowadays you can hardly find any free software (good or bad) that comes without ad/spyware or so. I simply declared my intentions and a little about the precautions I had taken to not spread viruses etc. My point is not to critize you, it is trivial software and it doesn't matter, but to make it obvious how many precautions "safe code" requires and thus how much there still is to fix in "software as we know it" .... be it debian or mikerowesoft under new ownership. Yes, agree. I do beleive, though that the code is safe, in terms of "hackability", even though it is crashable. |
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#13
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Baffle edge diffraction model, comments?
Peter Larsen wrote in message ...
Svante wrote: The program is available at: http://www.tolvan.com/diffract.exe Easy to crash if providing unexpected input, say a negative number of directions. Software that does not check for and discard unexpected input is vulnerable to buffer overflow. Not that that concern at all applies, I am not saying that this software is a security risk, but has been known and described in programming and software testing literature at least since 1979 that software must know how to handle also unexpected input. It should certainly not permit it via hitting a gadget with a mouse .... :-). No, of course this program is not intended for the "market". It just demonstrates my model and can easily be made to crash. I added the last lines because nowadays you can hardly find any free software (good or bad) that comes without ad/spyware or so. I simply declared my intentions and a little about the precautions I had taken to not spread viruses etc. My point is not to critize you, it is trivial software and it doesn't matter, but to make it obvious how many precautions "safe code" requires and thus how much there still is to fix in "software as we know it" .... be it debian or mikerowesoft under new ownership. Yes, agree. I do beleive, though that the code is safe, in terms of "hackability", even though it is crashable. |
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#14
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Baffle edge diffraction model, comments?
Peter Larsen wrote in message ...
Svante wrote: I am particularly interested in knowing if anyone has done more measurements that I could compare with, but any comments on the model/program are welcome! I love it and it fits the measurements I have of my System8 small reference monitor as I recall them. Interesting! Could you share these measurements, if possible? Thx. |
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#15
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Baffle edge diffraction model, comments?
Peter Larsen wrote in message ...
Svante wrote: I am particularly interested in knowing if anyone has done more measurements that I could compare with, but any comments on the model/program are welcome! I love it and it fits the measurements I have of my System8 small reference monitor as I recall them. Interesting! Could you share these measurements, if possible? Thx. |
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#16
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Baffle edge diffraction model, comments?
Peter Larsen wrote in message ...
Svante wrote: I am particularly interested in knowing if anyone has done more measurements that I could compare with, but any comments on the model/program are welcome! I love it and it fits the measurements I have of my System8 small reference monitor as I recall them. Interesting! Could you share these measurements, if possible? Thx. |
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#17
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Baffle edge diffraction model, comments?
Peter Larsen wrote in message ...
Svante wrote: I am particularly interested in knowing if anyone has done more measurements that I could compare with, but any comments on the model/program are welcome! I love it and it fits the measurements I have of my System8 small reference monitor as I recall them. Interesting! Could you share these measurements, if possible? Thx. |
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#18
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Baffle edge diffraction model, comments?
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#19
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Baffle edge diffraction model, comments?
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#21
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Baffle edge diffraction model, comments?
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#23
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Baffle edge diffraction model, comments?
On 29 Jan 2004 03:50:54 -0800, (Bob-Stanton)
wrote: (Svante) wrote in message . com... Hi all! I have spent some time trying to understand how to model edge diffraction of a loudspeaker baffle. A couple of years ago someone published a thread, in this group, that showed response curves of various shaped closed baffles. They showed that the best shape for a closed baffle was a sphere. I don't know if that was true, but a sphere has no edge. Do you think they were right? Bob Stanton The last thing you want in any speaker enclosure is symmetry about the driver. Whatever diffraction is present (and it is, whatever the shape) is intensified by the symmetry. In practice, straight sides are the best - they make for a smoothly changing diffraction source that will be free from frequency humps. As for that specific posting, I remember it. It was technical nonsense, using a piece of research concerning the effect of various body shapes in a plane wavefront - totally the opposite of a speaker. If you can imagine hanging such a shape between you and the speaker, that is what it examined. The poster presented a set of graphs with no units, and no idea what they meant. When questioned he was unable to advance a technical argument and just went off on a "this is published so it must be right" thing. d _____________________________ http://www.pearce.uk.com |
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#24
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Baffle edge diffraction model, comments?
On 29 Jan 2004 03:50:54 -0800, (Bob-Stanton)
wrote: (Svante) wrote in message . com... Hi all! I have spent some time trying to understand how to model edge diffraction of a loudspeaker baffle. A couple of years ago someone published a thread, in this group, that showed response curves of various shaped closed baffles. They showed that the best shape for a closed baffle was a sphere. I don't know if that was true, but a sphere has no edge. Do you think they were right? Bob Stanton The last thing you want in any speaker enclosure is symmetry about the driver. Whatever diffraction is present (and it is, whatever the shape) is intensified by the symmetry. In practice, straight sides are the best - they make for a smoothly changing diffraction source that will be free from frequency humps. As for that specific posting, I remember it. It was technical nonsense, using a piece of research concerning the effect of various body shapes in a plane wavefront - totally the opposite of a speaker. If you can imagine hanging such a shape between you and the speaker, that is what it examined. The poster presented a set of graphs with no units, and no idea what they meant. When questioned he was unable to advance a technical argument and just went off on a "this is published so it must be right" thing. d _____________________________ http://www.pearce.uk.com |
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#25
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Baffle edge diffraction model, comments?
On 29 Jan 2004 03:50:54 -0800, (Bob-Stanton)
wrote: (Svante) wrote in message . com... Hi all! I have spent some time trying to understand how to model edge diffraction of a loudspeaker baffle. A couple of years ago someone published a thread, in this group, that showed response curves of various shaped closed baffles. They showed that the best shape for a closed baffle was a sphere. I don't know if that was true, but a sphere has no edge. Do you think they were right? Bob Stanton The last thing you want in any speaker enclosure is symmetry about the driver. Whatever diffraction is present (and it is, whatever the shape) is intensified by the symmetry. In practice, straight sides are the best - they make for a smoothly changing diffraction source that will be free from frequency humps. As for that specific posting, I remember it. It was technical nonsense, using a piece of research concerning the effect of various body shapes in a plane wavefront - totally the opposite of a speaker. If you can imagine hanging such a shape between you and the speaker, that is what it examined. The poster presented a set of graphs with no units, and no idea what they meant. When questioned he was unable to advance a technical argument and just went off on a "this is published so it must be right" thing. d _____________________________ http://www.pearce.uk.com |
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#26
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Baffle edge diffraction model, comments?
(Bob-Stanton) wrote in message . com...
(Svante) wrote in message . com... Hi all! I have spent some time trying to understand how to model edge diffraction of a loudspeaker baffle. A couple of years ago someone published a thread, in this group, that showed response curves of various shaped closed baffles. They showed that the best shape for a closed baffle was a sphere. I don't know if that was true, but a sphere has no edge. Do you think they were right? Bob Stanton I don't know, but to me it seems like a bad shape. It is VERY symmetrical and for sure the sound will diffract around the sphere. What would happen (in my guessy world) is that the reflections (which WILL be a result of the diffraction) will come back simultanously from all possible paths around the sphere, and thus certain frequencies would be amplified maximally, others would cancel. I am guessing now, and I base my statement on my acoustic intuition (whatever that is worth) and the limited experience from the program I posted in this thread. It seems (with the program) as if the worst thing to do is to have symmetry. For example an circular edge on part of or the entire baffle increases the diffraction ripple. I feel that it would be the same with a sphere. Furthermore, the loudspeaker (dome?) would heve to have the same radius as the sphere for the "no edges" to be true. Also I recall a JAES article, by Geddes (Vol 49 #3 2001 pp 117-124) where he used a spherical cabinet to treat the effect of that the bass reflex vent is actually not close to the loudspeaker. Looking in directivity graphs in this article, it is obvious that the sound manages to "get round" the sphere. Another fact that would contradict the "has no edges" statement would be to take a normal box and just add rounded corners. That would not have edges either, and thus no diffraction would occur? Of course it would, and so it would around the sphere. I'll try to find that thread, do you remember its name? |
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#27
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Baffle edge diffraction model, comments?
(Bob-Stanton) wrote in message . com...
(Svante) wrote in message . com... Hi all! I have spent some time trying to understand how to model edge diffraction of a loudspeaker baffle. A couple of years ago someone published a thread, in this group, that showed response curves of various shaped closed baffles. They showed that the best shape for a closed baffle was a sphere. I don't know if that was true, but a sphere has no edge. Do you think they were right? Bob Stanton I don't know, but to me it seems like a bad shape. It is VERY symmetrical and for sure the sound will diffract around the sphere. What would happen (in my guessy world) is that the reflections (which WILL be a result of the diffraction) will come back simultanously from all possible paths around the sphere, and thus certain frequencies would be amplified maximally, others would cancel. I am guessing now, and I base my statement on my acoustic intuition (whatever that is worth) and the limited experience from the program I posted in this thread. It seems (with the program) as if the worst thing to do is to have symmetry. For example an circular edge on part of or the entire baffle increases the diffraction ripple. I feel that it would be the same with a sphere. Furthermore, the loudspeaker (dome?) would heve to have the same radius as the sphere for the "no edges" to be true. Also I recall a JAES article, by Geddes (Vol 49 #3 2001 pp 117-124) where he used a spherical cabinet to treat the effect of that the bass reflex vent is actually not close to the loudspeaker. Looking in directivity graphs in this article, it is obvious that the sound manages to "get round" the sphere. Another fact that would contradict the "has no edges" statement would be to take a normal box and just add rounded corners. That would not have edges either, and thus no diffraction would occur? Of course it would, and so it would around the sphere. I'll try to find that thread, do you remember its name? |
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#28
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Baffle edge diffraction model, comments?
(Bob-Stanton) wrote in message . com...
(Svante) wrote in message . com... Hi all! I have spent some time trying to understand how to model edge diffraction of a loudspeaker baffle. A couple of years ago someone published a thread, in this group, that showed response curves of various shaped closed baffles. They showed that the best shape for a closed baffle was a sphere. I don't know if that was true, but a sphere has no edge. Do you think they were right? Bob Stanton I don't know, but to me it seems like a bad shape. It is VERY symmetrical and for sure the sound will diffract around the sphere. What would happen (in my guessy world) is that the reflections (which WILL be a result of the diffraction) will come back simultanously from all possible paths around the sphere, and thus certain frequencies would be amplified maximally, others would cancel. I am guessing now, and I base my statement on my acoustic intuition (whatever that is worth) and the limited experience from the program I posted in this thread. It seems (with the program) as if the worst thing to do is to have symmetry. For example an circular edge on part of or the entire baffle increases the diffraction ripple. I feel that it would be the same with a sphere. Furthermore, the loudspeaker (dome?) would heve to have the same radius as the sphere for the "no edges" to be true. Also I recall a JAES article, by Geddes (Vol 49 #3 2001 pp 117-124) where he used a spherical cabinet to treat the effect of that the bass reflex vent is actually not close to the loudspeaker. Looking in directivity graphs in this article, it is obvious that the sound manages to "get round" the sphere. Another fact that would contradict the "has no edges" statement would be to take a normal box and just add rounded corners. That would not have edges either, and thus no diffraction would occur? Of course it would, and so it would around the sphere. I'll try to find that thread, do you remember its name? |
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#29
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Baffle edge diffraction model, comments?
(Bob-Stanton) wrote in message . com...
(Svante) wrote in message . com... Hi all! I have spent some time trying to understand how to model edge diffraction of a loudspeaker baffle. A couple of years ago someone published a thread, in this group, that showed response curves of various shaped closed baffles. They showed that the best shape for a closed baffle was a sphere. I don't know if that was true, but a sphere has no edge. Do you think they were right? Bob Stanton I don't know, but to me it seems like a bad shape. It is VERY symmetrical and for sure the sound will diffract around the sphere. What would happen (in my guessy world) is that the reflections (which WILL be a result of the diffraction) will come back simultanously from all possible paths around the sphere, and thus certain frequencies would be amplified maximally, others would cancel. I am guessing now, and I base my statement on my acoustic intuition (whatever that is worth) and the limited experience from the program I posted in this thread. It seems (with the program) as if the worst thing to do is to have symmetry. For example an circular edge on part of or the entire baffle increases the diffraction ripple. I feel that it would be the same with a sphere. Furthermore, the loudspeaker (dome?) would heve to have the same radius as the sphere for the "no edges" to be true. Also I recall a JAES article, by Geddes (Vol 49 #3 2001 pp 117-124) where he used a spherical cabinet to treat the effect of that the bass reflex vent is actually not close to the loudspeaker. Looking in directivity graphs in this article, it is obvious that the sound manages to "get round" the sphere. Another fact that would contradict the "has no edges" statement would be to take a normal box and just add rounded corners. That would not have edges either, and thus no diffraction would occur? Of course it would, and so it would around the sphere. I'll try to find that thread, do you remember its name? |
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#31
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Baffle edge diffraction model, comments?
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#32
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Baffle edge diffraction model, comments?
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#33
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Baffle edge diffraction model, comments?
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#34
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Baffle edge diffraction model, comments?
I was always under the impression that an egg would be the ideal cabinet
shape to address edge diffraction. With an egg, the distance to the curve is different in all directions and mirrored on the sides. "Robert Stanton" wrote in message m... (Svante) wrote in message Another fact that would contradict the "has no edges" statement would be to take a normal box and just add rounded corners. That would not have edges either, and thus no diffraction would occur? Of course it would, and so it would around the sphere. I'll try to find that thread, do you remember its name? I don't remember the name of the thread. The enclosure shape problem could be interesting to a person who writes programs. Sometimes when a closed form solution to a problem is very difficult, one solves it by iteration techniques. I have written optimization subroutines, and they often work very well. If someone knew the rules for calculating the frequency response of a (three dimentional) enclosure, he could write an optimization program for the best shape. The program would not be hard to write. Let's take it down to a simpler two-dimentional shape, a flat baffle. One could have a program that would vary the high to width ratio until the best best frequency response is obtained. Now, do the same thing for a three dimentional shape and you have an enclosure shape optimization program. Real easy to write. Well, maybe not *real* easy. Would you belive *very difficult* to write, but possible? :-) Once the program was written, you could give it optimization goals, and let it crank away. It might take a while to converge to a solution. You could turn your computer to the task, and then go to Florida for a week. When you come back, the computer will have found the best shape, for the optimization goals you gave. If that doesn't produce satisfactory results, give it a differnt set of optimization goals, (and go to Florida again :-) Bob Stanton |
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#35
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Baffle edge diffraction model, comments?
I was always under the impression that an egg would be the ideal cabinet
shape to address edge diffraction. With an egg, the distance to the curve is different in all directions and mirrored on the sides. "Robert Stanton" wrote in message m... (Svante) wrote in message Another fact that would contradict the "has no edges" statement would be to take a normal box and just add rounded corners. That would not have edges either, and thus no diffraction would occur? Of course it would, and so it would around the sphere. I'll try to find that thread, do you remember its name? I don't remember the name of the thread. The enclosure shape problem could be interesting to a person who writes programs. Sometimes when a closed form solution to a problem is very difficult, one solves it by iteration techniques. I have written optimization subroutines, and they often work very well. If someone knew the rules for calculating the frequency response of a (three dimentional) enclosure, he could write an optimization program for the best shape. The program would not be hard to write. Let's take it down to a simpler two-dimentional shape, a flat baffle. One could have a program that would vary the high to width ratio until the best best frequency response is obtained. Now, do the same thing for a three dimentional shape and you have an enclosure shape optimization program. Real easy to write. Well, maybe not *real* easy. Would you belive *very difficult* to write, but possible? :-) Once the program was written, you could give it optimization goals, and let it crank away. It might take a while to converge to a solution. You could turn your computer to the task, and then go to Florida for a week. When you come back, the computer will have found the best shape, for the optimization goals you gave. If that doesn't produce satisfactory results, give it a differnt set of optimization goals, (and go to Florida again :-) Bob Stanton |
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#36
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Baffle edge diffraction model, comments?
I was always under the impression that an egg would be the ideal cabinet
shape to address edge diffraction. With an egg, the distance to the curve is different in all directions and mirrored on the sides. "Robert Stanton" wrote in message m... (Svante) wrote in message Another fact that would contradict the "has no edges" statement would be to take a normal box and just add rounded corners. That would not have edges either, and thus no diffraction would occur? Of course it would, and so it would around the sphere. I'll try to find that thread, do you remember its name? I don't remember the name of the thread. The enclosure shape problem could be interesting to a person who writes programs. Sometimes when a closed form solution to a problem is very difficult, one solves it by iteration techniques. I have written optimization subroutines, and they often work very well. If someone knew the rules for calculating the frequency response of a (three dimentional) enclosure, he could write an optimization program for the best shape. The program would not be hard to write. Let's take it down to a simpler two-dimentional shape, a flat baffle. One could have a program that would vary the high to width ratio until the best best frequency response is obtained. Now, do the same thing for a three dimentional shape and you have an enclosure shape optimization program. Real easy to write. Well, maybe not *real* easy. Would you belive *very difficult* to write, but possible? :-) Once the program was written, you could give it optimization goals, and let it crank away. It might take a while to converge to a solution. You could turn your computer to the task, and then go to Florida for a week. When you come back, the computer will have found the best shape, for the optimization goals you gave. If that doesn't produce satisfactory results, give it a differnt set of optimization goals, (and go to Florida again :-) Bob Stanton |
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Baffle edge diffraction model, comments?
I was always under the impression that an egg would be the ideal cabinet
shape to address edge diffraction. With an egg, the distance to the curve is different in all directions and mirrored on the sides. "Robert Stanton" wrote in message m... (Svante) wrote in message Another fact that would contradict the "has no edges" statement would be to take a normal box and just add rounded corners. That would not have edges either, and thus no diffraction would occur? Of course it would, and so it would around the sphere. I'll try to find that thread, do you remember its name? I don't remember the name of the thread. The enclosure shape problem could be interesting to a person who writes programs. Sometimes when a closed form solution to a problem is very difficult, one solves it by iteration techniques. I have written optimization subroutines, and they often work very well. If someone knew the rules for calculating the frequency response of a (three dimentional) enclosure, he could write an optimization program for the best shape. The program would not be hard to write. Let's take it down to a simpler two-dimentional shape, a flat baffle. One could have a program that would vary the high to width ratio until the best best frequency response is obtained. Now, do the same thing for a three dimentional shape and you have an enclosure shape optimization program. Real easy to write. Well, maybe not *real* easy. Would you belive *very difficult* to write, but possible? :-) Once the program was written, you could give it optimization goals, and let it crank away. It might take a while to converge to a solution. You could turn your computer to the task, and then go to Florida for a week. When you come back, the computer will have found the best shape, for the optimization goals you gave. If that doesn't produce satisfactory results, give it a differnt set of optimization goals, (and go to Florida again :-) Bob Stanton |
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Baffle edge diffraction model, comments?
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Baffle edge diffraction model, comments?
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