The effects of mutual coupling and efficiency increases when using multiple subs can be looked and varified up in textbooks on sound reproduction, especially those that deal with professional installations that are more likely to use multiple subs. The "Handbook of Sound System Design" by John Eargle (of JBL Professional) is a good place to start.

The exact same principles apply to home installations as they do to professional ones - the same laws of physics apply.

Maybe they don't apply to some people though.

[This message has been edited by soundhound (edited August 24, 2004).]