Cabinet Volume for Line Array

[ralph-bway]

Hi All,

I'm confused about the actual volume needed for the following project.

I'd like to make a line array using two of these peerless drivers

http://www.partsexpress.com/pe/showd...number=297-616

and 9 of these Audax mid-bass drivers per side

http://www.partsexpress.com/pe/pshow...number=299-434

From the specs at PE the peerless VAS are 4.8 CF each but when I load the specs in WinISD I get a little under 3 CF for BOTH drivers in a sealed box.

The Audax VAS are .6 CF each, but in WinISD I get 22.5 CF for nine drivers.

Am I misunderstanding the VAS spec?

What would be the optimum cabinet volume for all 11 drivers?

When combining different drivers is the total volume needed calculated by adding 3 CF for the peerless plus 6 CF for the Audax equals 9 CF, or do you need less since the drivers are operating in different frequency ranges.

Thanks

[BillFitzmaurice]

Your need to have separate rear chambers for each driver set or the IM distortion will be quite untenable. For cabinet volume simply go to WinISD and model the box with the number of drivers you have to get each respective sub-box volume. It seems that maybe you did that but are confused at the result, and here's why:

In the relationship between Vas and box volume the other T/S specs are also contributory in the final result, most especially the Qts. In this case when modelling the midbass drivers make sure you do so with your intended crossover frequency, and not the default optimized frequency that the program will use. If going closed box fudge around with the box size till you get it as small as possible while flat to the Fc; the resulting response peak below Fc has to be flattened out with your crossover.

Depending on where you plan to crossover you might want to go with a midbass driver with a higher Fs and lower Qts for a better result.

[ralph-bway]

Thanks for the help & info Bill