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Old 30th November 2012, 02:05 AM   #1
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Default Maple/Mathematica/Matlab hornresp program

I am looking at modelling a horn response similar to what David McBean did in his 'hornresp' program, but using probably Maple or Mathematica. I would be interested to know if anyone else has attempted this. I don't want to reinvent the wheel.

I also am wondering what model David McBean used in hornresp. The only comment I can find is that his work is based on Olson's horn model. If anyone (David I don't know if you will read this) knows more about the specifics of what was put into the hornresp program in terms of the physics, assumptions and equations I would appreciate hearing about. As I hope to develop such a model in Maple and/or Mathematica, I will share my results after I have had a chance to check it against David McBean's hornresp program. My background is a Ph.D. in physics with a strong mathematical background. I have previously written programs in Maple and Matlab, and am trying to come up to speed in Mathematica.

Thanks for any help any one can offer.
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Old 30th November 2012, 02:49 AM   #2
jcx is online now jcx  United States
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might check for Dr Earl Geddes work, he posts here as GedLee

has refs at the end of his article http://www.gedlee.com/downloads/Horn...ry%20reply.pdf

for the diy audio community you might consider open source/free math sw, Octave, SciLab are free Matlib workalikes, for symbolic math sympy Python package, and the SageMath project - which includes Macsyma
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Old 30th November 2012, 02:55 AM   #3
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Take care with Harry Olsen's calculations. They were done by slide-rule, and are incomplete. Look up Don Keele, and his work to get more.
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Old 30th November 2012, 03:17 AM   #4
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I'd second the suggestion from jcx, consider the open source equivalents. I especially like the scipy/numpy/ipython/matplotlib/sympy tools and they really have come forward to be very viable and productive development environment recently and are very much aimed at scientific community wanting to just get in and be productive without having to worry too much about the programming side of things.

iPython is one tool I have really found very useful lately with its new features such as 'notebooks' that let you do development in a web browser and make prototyping blocks of code simple fast and interactive.
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Old 30th November 2012, 06:42 AM   #5
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Hi joeladis,

Most of the theory required to develop a horn loudspeaker simulation program can be found in the book "Acoustical Engineering" by Harry F. Olson.

"Acoustics" by Leo L. Beranek is also a useful text.

Kind regards,

David
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Old 30th November 2012, 04:54 PM   #6
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Default Thanks to all for reply on maple etc hornresp program

Thanks to all who responded so quickly to my post. Firstly, I already own copies of Maple, etc. My desire is to have a program that can be shared with enough detail to allow mods by knowledgeable users. I have modeled some of what is in Leach's book, and would like to get a good working model of a horn.

What David McBean has done is excellent (thank you, David for the reply). As a physicist I am interested in modeling and refining the model as I go along.

I don't know what the etiquette is, but if possible I would like to contact you, David, by email as I have some specifics to ask/share with you. Also, thanks all for info suggestions, I own most of the relevant texts, and have been in touch previously with Earl Geddes.
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Old 1st December 2012, 06:01 AM   #7
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Quote:
Originally Posted by joeladis View Post
if possible I would like to contact you, David, by email as I have some specifics to ask/share with you.
Hi joeladis,

To contact me by email, click on my name on the Hornresp webpage. Please note though - while I am happy to discuss horn theory in general I am not prepared to release details of the specific models, techniques or algorithms used in Hornresp. Making the software available free of charge and providing comprehensive support to users, is the best that I can do :-).

Kind regards,

David
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Old 5th December 2012, 04:03 AM   #8
jcx is online now jcx  United States
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just ran across http://diy-audio.narod.ru/litr/Model...Enclosures.pdf Horns and Enclosures '94 PhD thesis

I'm not conversant in the physics for 3d waves so can't properly critique - but looks interesting - outlines FDM wave models based in Spice electrical analogs

Last edited by jcx; 5th December 2012 at 04:32 AM.
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Old 5th December 2012, 05:00 PM   #9
schmeet is offline schmeet  United Kingdom
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I'd also recommend looking at www.quarter-wave.com
This is the best resource I have come across so far.

Also, you say you are not interested in re-inventing the wheel. However, that sounds exactly like what you are attempting to do. I'm not saying you shouldn't, i do it on a daily basis, but you should accept the fact that you are!
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Old 13th February 2013, 06:24 PM   #10
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Default Matlab Horn Program Zip File

As I promised in an earlier post (30 Nov 2012), this is the first installment of a set of programs I intend to make available to the DiY community. The Zip file, MatlabHornFiles.zip, contains a Matlab program that can be used to calculate the acoustic input impedance of a multi-segment horn that consists of any combination of cylindrical, conical and exponential segments. The Zip file also contains detailed instructions on using the Matlab program, which itself is heavily commented. The program should run on any platform on which Matlab runs. Please first read the 'Read Me First' and 'Disclaimer' files also contained in the Zip file.

Finally, I would like to thank David McBean for his communications that pointed me in fruitful directions, and for suggesting some minor corrections to what I intended to upload. I also appreciate his willingness to allow me to include comparison plots of the Matlab output with his Hornresp program.
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File Type: zip MatlabHornFiles.zip (462.7 KB, 73 views)
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