miwa

what is the purpose of phase reverse on a subwoofer?

Southbound

I'm only guessing, but maybe to cause some kind of slight reverb effect??? Or maybe to help cancel a possible ground loop problem, if one were to occur? I'm sure somebody else knows more about subwoofers. I'm more of a fullrange stereo person.

SuperDave

I sort of talked about phase reverse in your post on bass lag. Here are two different phase scenarios and how they react.

Normal phase (positive amp speaker output to positive input on sub & negative amp speaker output to negative input on sub)
Initial music plays sub cone out away from magnet

Reverse phase (negative amp speaker output to positive input on sub & positive amp speaker output to negative input on sub)
Initial music plays sub cone in towards magnet

Since soundwaves follow the movement of the cone, reversing phase causes a slight delay since the initial soundwaves go into the box.

To complicate things, you can't just figure that normal phase wiring will result in the sub being truly in phase. A crossover can change the phase of the speaker output. A bridged amp could also result in a shift in the phase of the speaker output. Since you aren't sure which way the phase might actually be coming out of your amp, try it both ways to see what sounds better. You can also do this with your other speakers in addition to your sub.

David

miwa

hmm.. so in theory, I can wire the interior speakers with a phase delay so that the sub can catch up with it maybe...