The phase control on your subwoofer crossover is to help make sure that your subs and main speakers are "in phase"(obviously). That simply means that your sub & main drivers will be moving in the same direction at the same time - in and out.
Sounds obvious, but this isn't automatically true. Most times they will be moving in the opposite direction or some degree out of time. The result of "out of phase" drivers (relating to bass) is that the out of synch signals end up cancelling each other out(to some degree), or what audio techs call a "null". So, instead of getting bass enhancement from adding subwoofers, you end up with less bass. Sometimes, a lot less bass.
The calibration/markings on the phase control of a subwoofer crossover, often a "0-180" degree switch or a variable "0-360" dial" simple provide a repeatable setting. The value doesn't really mean anything more than that. What works, works, regardless of the number associated with it.
You normally can turn the phase dial while bass heavy music is playing and notice that at some point the bass will start to get louder and then past a point start to get softer. This is rudimentary way of hearing the effect of phase. But, it is no way to set it properly because what you hear next to the sub/crossover probably will not be the same at the listening position. There can be several areas with nulls and peaks within every room, some up to 30x louder of softer.
There are a myriad of ways to test and fine tune phase alignment, but a sure-fire, easy to do, method is(quoting a post on AVguide.com):
1) reverse the red and black speaker leads going to your left and right speakers. Leave the wiring on your subwoofer alone.
2)Play a test tone at the crossover frequency (you can find tones on most test CDs) and have someone adjust the phase control while you sit in the listening position.
3)Turn the phase control until you hear the least amount of bass.
4)Return the speaker leads to their correct polarity and the sub is perfectly dialed-in.
By reversing the red and black leads on your speaker, you are putting them out of phase with the sub. When you hear the least bass, the main speakers and the sub are maximally out of phase. When you return the speaker leads to their correct position, the sub and main speakers are maximally in-phase.
It is much easier to dial-in a maximum null than a maximum peak.
Hope this helps and if I got something wrong, I hope someone with more experience will step in and correct it.
Sounds obvious, but this isn't automatically true. Most times they will be moving in the opposite direction or some degree out of time. The result of "out of phase" drivers (relating to bass) is that the out of synch signals end up cancelling each other out(to some degree), or what audio techs call a "null". So, instead of getting bass enhancement from adding subwoofers, you end up with less bass. Sometimes, a lot less bass.
The calibration/markings on the phase control of a subwoofer crossover, often a "0-180" degree switch or a variable "0-360" dial" simple provide a repeatable setting. The value doesn't really mean anything more than that. What works, works, regardless of the number associated with it.
You normally can turn the phase dial while bass heavy music is playing and notice that at some point the bass will start to get louder and then past a point start to get softer. This is rudimentary way of hearing the effect of phase. But, it is no way to set it properly because what you hear next to the sub/crossover probably will not be the same at the listening position. There can be several areas with nulls and peaks within every room, some up to 30x louder of softer.
There are a myriad of ways to test and fine tune phase alignment, but a sure-fire, easy to do, method is(quoting a post on AVguide.com):
1) reverse the red and black speaker leads going to your left and right speakers. Leave the wiring on your subwoofer alone.
2)Play a test tone at the crossover frequency (you can find tones on most test CDs) and have someone adjust the phase control while you sit in the listening position.
3)Turn the phase control until you hear the least amount of bass.
4)Return the speaker leads to their correct polarity and the sub is perfectly dialed-in.
By reversing the red and black leads on your speaker, you are putting them out of phase with the sub. When you hear the least bass, the main speakers and the sub are maximally out of phase. When you return the speaker leads to their correct position, the sub and main speakers are maximally in-phase.
It is much easier to dial-in a maximum null than a maximum peak.
Hope this helps and if I got something wrong, I hope someone with more experience will step in and correct it.