If I put two subs in a shared air sealed box and the recommended volume per sub was 1.0 cu ft how big would I need to build the box?

I'm expecting people to tell me 2.0 cu ft, but I heard that the box volume will decrease and the efficency will increase with shared air, was I lied to, and if not what is the formula to calculate?

Another question is if I put fiber fill, or whatever everyone calls it, what difference will it make to the sub response and what is the formula for that?

Thanks,
ROb [img]graemlins/freak.gif[/img]

 

Polyfill, or polyester filling (pillows etc) lowers Fs and Qtc (In a sealed enclosure) through miniscule vibrations of the fibers themselves, thus dissapating heat. The general rule is 16oz per cubic foot. Too little or too much will have the opposite effect you're looking for. Don't think of it as simply a replacement for not building a large enough sealed enclosure, though.

 

Your expectation is right 2.0^3". Sounds like some guy is making up reasons why his box is smaller than it should be when housing two woofers. If there is any increase in efficiency it will be so minimal that it will only register with precise instruments. Build the 2 cube box and you will be happy.