Undivided Sealed Enclosure Response With Multiple Drivers...
 

This may sound like a stupid question, but I have yet to find someone who can give me a good answer to it:

How do multiple drivers react when installed in a single undivided sealed enclosure - with regard to (Fb/F3 etc.)?

For instance - Say you install 4 12" drivers in a single undivided 4.0 ft3 (Net) enclosure. Do the woofers react as if each driver was installed in it's own 1.0 ft3 box, as if each was installed in it's own 4.0 Ft3 box, or Somewhere in between?

If so, is there some easy formula to calculate the volume that each driver "sees" to determine box response characteristics?

Thanks,

Hans

Yes if you install multiples of the same driver in one box you simply multiply the vb by the # of drivers.

You could try figuring it out yourself with a little experiment in a normal loudspeaker simulation program. Look at the response of one driver in volume of x liters, the response of n drivers in the volume n*x and the response of n drivers in the volume x. The first two are probably the same graphs, the third will have a higher cutoff.

Multiply the box volume with the number of drivers, and the response (but not nessecarily the sensitivity) will be the same.

Here is how it turns out in Basta!:

http://www.tolvan.com/multidriver.gif

(The black curve lies under the pink curve)

I was expecting more difference from 1x in 25 litres to 2x in 25 litres. Maybe it's just the large y-scale putting me off.

Well, in this case fc changes from 53 to 65 Hz. Qtc changes from 0.7 to 0.85. What may be confusing is that there is an baffle step in the picture as well, that is not compensated for.

Here is the same graph without the baffle step:

http://www.tolvan.com/multidriver2.gif