Ts parameters and multiple drivers
 

How would one figure the ts paramters of two drivers, so they could be modeled as one? would VAS, and QTS double? What about QES if the drivers were wired in series? and parallel? and what about QMS? :)

If you go to my site and look under the general speaker articles there is a write-up that answers your questions. I have a sample problem that should help explain the pro's and con's of each type of wiring.

Hope that helps,

Thanks for the reply! I know about both types of wiring, just never had to model them this way before. :)

Read the article.. while it is helpful, I don't think it gave me everything I need.. Am I completely blind? :)

All that is really significant is the Vas, which doubles assuming you're not going isobaric, and halves if you do. Model in WinISD; it will model as many drivers as you wish. Series versus parallel is 90% a matter of just keeping the total load where your amp is happy with it. You can get more picky if you wish, but keeping the impedance load within the usual 4 to 8 ohm window also keeps everything else from getting hinky as well.

Based on your original question, I believe that everything you need to define an equivalent driver to model two drivers in series or in parallel is provided in the write-up. If you compare the three sample simulation inputs, you will find the modifications to Re, BL, Sd, and Vad required and the impact on SPL at 1 m for 1 watt input and system impedance. You should be able to derive an equivalent driver and use it in a simple T/S analysis of a ported or sealed enclosure. Not sure what else I can provide or reference.

Thanks for the help, but I'm not doing just a simple ported enclosure. If I were, I could just use winisd and select two drivers :) I'll keep on google searching :)

If
"a" is the number of elements that are connected in series, electrically,
"b" is 1 for normal configuration, 2 for isobaric configuration and
"n" is the total number of elements, the new values are calculated as:

Vas=Vas1*n/b^2
Bl=Bl1*a
Sd=Sd1*n/b
Re=Re1*a^2/n
Le=Le1*a^2/n

So two drivers in series, side by side has a=2, b=1, n=2 and
Vas=2*Vas1
Bl=2*Bl1
Sd=2*Sd1
Re=2*Re1
Le=2*Le1

Perfect!! Thanks a ton! :up: