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#1
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Using computer progs to design speakers?
Hi,
How good results can you get by using computer programs to design speakers? There are many such progs available. How much trust would you place into the results? If you make a cool design by a program and build it, what can you expect in reality? Can you recommend some good progs that would work? What are the most useful? And how can you get most use of them? Any thoughts? Info much appreciated. -at |
#2
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Using computer progs to design speakers?
"at" wrote in message
How good results can you get by using computer programs to design speakers? First, that depends on whether you're designing a subwoofer (easier, fairly straight-forware) or a full range system (much more difficult and tricky). There are many such progs available. How much trust would you place into the results? At worst, the best of them are good starting points. Doing it right takes a lot of legwork. For example, passive crossver design "by the book" starts with a full set of frequency response and complex impedance curves for each driver. At the least, a good program will simulate the performance of the design you give it parameters for. This is a big help because you can run a lot of simulations in the same time it would take you properly evaluate something you tried in the real world. If you make a cool design by a program and build it, what can you expect in reality? AFAIK many professional designers start out with a theoretical design, and then polish it in the lab and listening room. Can you recommend some good progs that would work? What are the most useful? And how can you get most use of them? Any thoughts? Info much appreciated. You can "rent" a program by having retailers like Madisound make the design for you with their software. |
#3
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Using computer progs to design speakers?
"at" wrote in
: Hi, How good results can you get by using computer programs to design speakers? There are many such progs available. How much trust would you place into the results? If you make a cool design by a program and build it, what can you expect in reality? Can you recommend some good progs that would work? What are the most useful? And how can you get most use of them? Any thoughts? Info much appreciated. -at I wrote my own program years ago and it worked pretty good. As in all things, there is a little tuning to be done after it is built. If you don't trust the programs, you could always do the math with a pencil and paper. r -- Nothing beats the bandwidth of a station wagon filled with DLT tapes. |
#4
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Using computer progs to design speakers?
"at" wrote in message ...
How good results can you get by using computer programs to design speakers? There are many such progs available. How much trust would you place into the results? If you make a cool design by a program and build it, what can you expect in reality? Can you recommend some good progs that would work? What are the most useful? And how can you get most use of them? The accuracy of these programs is limited by a number of contraints: 1. Your understanding of the limits of the model. Any program based on, for example, the Thiele-Small model will work well (given other contraints listed here) in predicting the resulting response with in the piston band of the system, but will not include diffraction and baffle effects. If you expect the predicted response of a 12" woofer at 800 Hz to be accurate, you WILL be disappointed because you did not understand the limits of the model. 2. As in all such excercises, garbage in give garbage out. And that means if you plug in driver parameters from a catalog or a spec sheet and expect the results to reflect reality you WILL be disaapointed, because you failed to account for the fact that there can (and often is) large variations in the operating parameters of drivers AND differences between the specs and purchased reality. Similarily, the performance and drivers changes with conditions, and if by not accounting for these changes you design a system that violates the constraints, you WILL be disappointed in the results. 3. The sophistication of the model and the accuracy of the model description. If you make assumptions about some of the detailed parameters of the design, you WILL be disappointed. For example, you design a system which assumes perfect absorbtion in the enclosu if your design depends upon that assumption, you WILL be disappointed in the result, because you made unrealistic assumptions Now, notice that all of the above comments have the operative word "you" as the agent of failure. This is based on my experience extending over 30 years of doing this wort of work, more importantrly, of watching many others do it. My observations show clearly that the discrepancy between the predicted design and implemented reality is due almost entirely to the program user: that person's failure to understand what the model does and what its limitations are, providing unrealistic parameters to the program, and making unrealistic assumptions about the design. I have seen a half dozen speaker design programs take the same garbage data and result in the same garbage design, and those same half-dozen programs take the same good data and operating under the same reasonable contraints spit out a VERY competent and realizable design. Now, beyond that, there's another factor you didn't ask about. While all of the programs, within their constraints, do a very reasonable job, some of them a simply miserable to USE because the person who wrote the program spent most of their time working on implementing the math and NO time on dealing with simple usability issues. What good is the most sophisticated, realistic modeling program if you end up being so frustrated using it that you're ready to shoot the computer followed by yourself? This problem, regrattbly, plagues more programs than it should, and it's not just limited to speaker software, to be sure. An example of this are the older versions of LMS. It's a VERY good mathematical model under the hood, but it has a LOUSY user interface. I don't know if they've cleaned it up or not, but it was bad enough that I found it difficult to recommend even considering the sophistication of the model. It also was buggy in the sense that you could see gross mathematical truncation or roundoff errors occuring in plots. |
#5
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Using computer progs to design speakers?
On Tue, 3 Aug 2004 12:50:26 +0300, "at"
wrote: Hi, How good results can you get by using computer programs to design speakers? There are many such progs available. How much trust would you place into the results? If you make a cool design by a program and build it, what can you expect in reality? Can you recommend some good progs that would work? What are the most useful? And how can you get most use of them? Any thoughts? Info much appreciated. -at Do bear in mind that these computer programmes generally deal with nothing deeper than the physical conditions surrounding the fundamental resonance of a speaker driver. They will help you with gross alignment and tuning of a cabinet, but they have nothing within them that addresses the way a driver actually sounds. That you must do by ear, either by persuading manufacturers to donate freebies for testing, or by listening to speakers that contain drivers on your candidate list. The maths itself is pretty straightforward, and the computer programmes are really not much more than a convenient and pretty front end. You can do the sums and produce graphs in a spreadsheet very easily once you have read up on the theory. I dare say there are programmes that delve rather more deeply into the physics and mechanical properties of drivers and cabinets, but my bet is that these are proprietory to manufacturers, and they won't let you have a copy. d Pearce Consulting http://www.pearce.uk.com |
#6
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Using computer progs to design speakers?
Thank you very much for your thoughts. This is excellent advice.
Thanks! -at "Dick Pierce" wrote in message om... "at" wrote in message ... How good results can you get by using computer programs to design speakers? There are many such progs available. How much trust would you place into the results? If you make a cool design by a program and build it, what can you expect in reality? Can you recommend some good progs that would work? What are the most useful? And how can you get most use of them? The accuracy of these programs is limited by a number of contraints: 1. Your understanding of the limits of the model. Any program based on, for example, the Thiele-Small model will work well (given other contraints listed here) in predicting the resulting response with in the piston band of the system, but will not include diffraction and baffle effects. If you expect the predicted response of a 12" woofer at 800 Hz to be accurate, you WILL be disappointed because you did not understand the limits of the model. 2. As in all such excercises, garbage in give garbage out. And that means if you plug in driver parameters from a catalog or a spec sheet and expect the results to reflect reality you WILL be disaapointed, because you failed to account for the fact that there can (and often is) large variations in the operating parameters of drivers AND differences between the specs and purchased reality. Similarily, the performance and drivers changes with conditions, and if by not accounting for these changes you design a system that violates the constraints, you WILL be disappointed in the results. 3. The sophistication of the model and the accuracy of the model description. If you make assumptions about some of the detailed parameters of the design, you WILL be disappointed. For example, you design a system which assumes perfect absorbtion in the enclosu if your design depends upon that assumption, you WILL be disappointed in the result, because you made unrealistic assumptions Now, notice that all of the above comments have the operative word "you" as the agent of failure. This is based on my experience extending over 30 years of doing this wort of work, more importantrly, of watching many others do it. My observations show clearly that the discrepancy between the predicted design and implemented reality is due almost entirely to the program user: that person's failure to understand what the model does and what its limitations are, providing unrealistic parameters to the program, and making unrealistic assumptions about the design. I have seen a half dozen speaker design programs take the same garbage data and result in the same garbage design, and those same half-dozen programs take the same good data and operating under the same reasonable contraints spit out a VERY competent and realizable design. Now, beyond that, there's another factor you didn't ask about. While all of the programs, within their constraints, do a very reasonable job, some of them a simply miserable to USE because the person who wrote the program spent most of their time working on implementing the math and NO time on dealing with simple usability issues. What good is the most sophisticated, realistic modeling program if you end up being so frustrated using it that you're ready to shoot the computer followed by yourself? This problem, regrattbly, plagues more programs than it should, and it's not just limited to speaker software, to be sure. An example of this are the older versions of LMS. It's a VERY good mathematical model under the hood, but it has a LOUSY user interface. I don't know if they've cleaned it up or not, but it was bad enough that I found it difficult to recommend even considering the sophistication of the model. It also was buggy in the sense that you could see gross mathematical truncation or roundoff errors occuring in plots. |
#7
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at wrote:
Hi, How good results can you get by using computer programs to design speakers? The designer still makes the choices. Can you recommend some good progs that would work? CALSOD What are the most useful? I don't know, there are others. Some probably have steeper learning curves than others, all are highly likely to require that you can design loudspeakers without them. And how can you get most use of them? Climb the learning curve. Any thoughts? Info much appreciated. A good design will help you get it simple. Rethink if it has to be complicated. Learn what imperfections to accept and what to worry about, some imperfection is unavoidable in a practical design, the art of the designer is (also) the art of choosing wisely. -at Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
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