Car Audio Central - Ultimate Car Audio Forum and Community

The following site tells you everything you need to know to build your own enclosure:
http://www.xtant.com/html/techSupport/enclosures.cfm

This site covers calculations, theory, materials and technique for building the following boxes:
sealed
ported
infinite baffle
fourth order bandpass
sixth order bandpass
multiple driver
isobaric

for information on:
dipole
transmission line
passive radiator

see the following site:
www.diysubwoofers.org

Here is a link to some helpful formula's ofr figuring your airspace:
MTX Formula's

If you still have questions, feel free to post them to our speaker help forum.