Originally Posted by jbrown15
Okay I see what you're saying but "IF" we take the numbers I was giving by Tom and the XS30 in the 40hz and up range it would have an output advantage of about 4.5db. Which is basically twice the output of the FV15HP in that range.
You're only going to get 6db by doubling up on subs if they are located together, and I don't think that would be very practice. So realistically you would probably have on in each corner which would only be about 4db with two of the same subs.
In the 40hz and up range the XV15 doesn't even come close to the XS30.
Remembering of course that it takes twice the power to raise SPL 3db but it takes 10dB to have the perception of doubling sound level; that sounds twice as loud. Based on that, in my opinion, 3dB isn't worth getting out of bed for other than trying to create a flat graph and when peaks and mounds are adjusted for, advantages in the mid-bass range of three to six dB are adjusted accordingly for.
The point, one needs to take meaningful consideration into consideration when having discussions of this kind.
My understanding of co-location is, they need to be within one wave length of each other for co-location to be effective. That means to get full benefit of the LFE channel, the subs need to be within ~9.5' and to take benefit of <80Hz frequencies where most LFE content lies, the subs need to be within ~19' of each other. Wave length; (V/f) V=speed of sound, at sea level, dry air, at 68F is 1128 ft/s and f=frequency is the frequency being asked about.