[Mike P.]

An infinite baffle is really a large sealed enclosure. The optimum size of a infinite baffle is 10 times the Vas of the driver. They are usually built into a wall or ceiing with the area at the back of the sub providing the "cabinet".

I can't find any information on a "peavey dth 215", can you give us some more information so we know what we're dealing with.

 

[Mike P.]

Is this what you have?

http://www.peavey.com/assets/literature/manuals/80304444.pdf

 

[Mike P.]

That is the 1505-8DT driver with a Fs of 44.2 hz and a Xmax of 4.8 mm. It is not designed to play any lower than what it is. The box is tuned to 47 hz, you might get away with a 40 hz tuning but that's about it.