How to model a closed box speaker??

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Hi I'm an EE student, and have chosen to study speakers as a theme during this semester.

The problem is that the school I'm attending don't have any teachers with experience in speaker design, and I therfor turn to you guys and girls.

I would like to model a closed box, but I only have a model (with resistors coils transformers etc.) I don't have the values for these components. I'd really like to calculate the model, eventhou it's been done before, but I'm not sure where to start.

I would like to compare my own results with those found using the Thiele Small model parameters.

If anybody know anything or have papers from AES, I would love to see them, as I'm starting from scratch.

Ohh yes and it's only the low freq model I'm working on (to start with) :)

Thanks in advance

\Jens
 
diyAudio Moderator Emeritus
Joined 2001
I have the Journal of The Audio Engineering Society Loudspeaker Anthology Parts I and part of Part II.

I can post the circuit here and Email the article to you. It will be done today or tomorrow.

I am thinking of an article by Small. I believe there might also be an article by Bart Locanthi.

If I haven't given you the Email or posted on this thread by tomorrow, "bump" this to the top of the list by requesting again.
 
frugal-phile™
Joined 2001
Paid Member
You need to get a copy of Beranek's (sp?) book on the subject. It goes heavily into the electrical modeling of speaker systems. It would be an invaluable resource.

I'll see if i can dig my copy out of the library and get a proper title, ISBN etc. (it is mentioned i believe in another thread if you want to try to search it out)

dave
 
Also worth a look is :

Introduction to Electroacoustics and Audio Amplifier Design
W Marshall Leach Jr
ISBN 0-7872-7861-0

It's got some really thorough mathematical/electrical analysis in it as well as good background material. The man is a bit of a legend and much underrated imho.
 
....ooops, read the thread too fast and didn't see it had already been mentioned. spot the idiot....... :clown:

also worth mentioning that i've always found the box design stuff in Beranek to be a bit brief in places and definitely not as good as that in Marshall Leach Jr.
 
diyAudio Moderator Emeritus
Joined 2001
My sincere apologies. I am having trouble with this damn scanner. It was bought less than a year ago.

Everything is fine on it except that there is a thin line down the middle that looks like somebody ran down it with an eraser.

By going greyscale, I can eliminate most of it and make it readable. But it is a struggle. I have spent some time on this.

My original intention was to send you two articles by Small
A) Modeling a loudspeaker unenclosed-to acquaint you with the terminilogy-and
B) Modeling a loudspeaker in a closed box.

I was also going to include Bart Locanthi's earlier and shorter article, which also modeled in a closed box and served as the basis for Small.

All three articles are from the Journal of the Audio Engineering Society.

If I cannot get you Small's article due to technical difficulties, I will try to get you Locanthi's shorter article.

Sorry.
 
I'd also recommend Leach's book. I don't have a copy, but based on the quality of his AES articles, I bet his book is a must-have. Leach's Computer Aided Electroacoustic Design with SPICE JAES article is what jumpstarted me on this hobby (after reading John Borwick's Loudspeaker and Headphone Handbook).

Have you tried nearby engineering/architecture libraries? There might be some JAES issues there.

Isaac
 
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