physics equations

[slackerbob]

does anyone know the actual equations you use to calculate box volumes and resonant frequencies? I'd rather do the math myself and know it's done right than rely on computer programs and such to do it for me behing the scenes.

thanks

[theChris]

i beleive winISD has a section in the help file about conventional models of boxes. may be a start.

[mikee12345]

http://www.diysubwoofers.org/sld/sealed1.htm


http://www.diysubwoofers.org/prt/ported1.htm



btw winisd has been compared with several other programs-its close.

[dekkersj]

Actually, this is the first time for me in this forum. Your question regarding the real physics behind a loudspeaker is not simple, apart from some simple equations which can be seen everywhere around. My best guess would be the famous book of Beranek. Here, the elektro-acoustical model is presented and transformed into a equivalent elektro model. Good luck!

[SY]

There's no substitute for going back and reading the Thiel and Small papers. What you'll find is that the equations are (with the exception of closed boxes) not solvable in closed form- you have to evaluate them numerically. That's why they're normally provided as tables.

[slackerbob]

where might I find a copy of these papers? were they published anywhere?

[SY]

JAES. I think AudioXpress sells a book of AES reprints that includes those foundational papers.

[sianturi]

Hello Slackerbob,

I have those T/S paper in scanned version, courtesy of a member here (I think it was from f4rier). If my memory serves me right, it was in tiff format.

If you want it, I can send it to your email.
BUT, I don't have it now. I am now in my office and the paper is in my PC at home. Tomorrow, maybe I can send it to you.

Just tell me if ya want it to be sent to your mail.

Cheers,

[yeti]

Please sent me a copy too!

Thanks in advance.

[Pjotr]

Originally posted by SY

There's no substitute for going back and reading the Thiel and Small papers. What you'll find is that the equations are (with the exception of closed boxes) not solvable in closed form- you have to evaluate them numerically. That's why they're normally provided as tables.

Duh…? What do you mean by that? A closed box system is simply a 2nd order mass-spring system and a BR/PR box a 4th order mass-spring system as far as it concerns the TS model. I don’t see why that is not solvable in closed form with regard to spl, impedance etc.

BTW it is not that difficult to model a speaker system by means of control theory with real masses and springs in stead of the electrical equivalent of Thiele and Small and many others.

Cheers