Phase Invertion

[point_and_shoot]

My subwoofer has a phase invertion button on the back. When would I ever need to use this? I can't tell much difference when I listen either way.

[Guest Anonymous]

Well, one reason is, and the less common is because some compainies build their amps out of phase on purpose ie conrad johnson....

Best,

George

[DrWho]

The phase switch is used to better integrate your sub with your mains. Any time you get two sources out of phase you get deconstructive interference (the sound cancels out). If you don't hear much of a difference either way, then your sub's location relative to the mains is probably such that they are about 90 degrees out of phase at the listening position throughout the crossover region...flipping the switch will just put them 90 degrees out of phase the other direction.

Does your subwoofer also have a phase dial? If so, then the phase switch can be used to make dialing in the sub that much easier...what you do is turn the phase dial until you get as little bass as possible, effectively putting your sub 180 degrees out of phase. Then you flip the switch and now your sub is in phase and you have the most bass as possible. Dialing in the sub this way is easier because it's easier to hear things when they're out of phase than when they're in phase. The reason being that out of phase ideally results in a 0dB signal (so even if everything is playing at 100dB, the output in the crossover region will be 0dB). If the subs and mains were in phase, you would at most experience 6dB increase in sound (so that's 106dB max without a crossover). But with the crossover in action, both speakers are -3dB at the crossover, so this 106dB max actually becomes 100dB, which isn't any louder than everything else, and thus is practically impossible to hear.

[point_and_shoot]

OK. That is a little deep for my feeble mind but I will give it a shot nevertheless. Thanks!