Originally Posted by Nics1246
Hmm, thanks for the response but not sure I quite understand. Who would put in the speaker wires backwards? So it does not change the sound of the bass then right?
If one of your front speakers was wired backwards relative to the other, they would be 'out of phase' with one another. Very basically, what this causes is that when one speaker's woofer is 'vibrating' forward, the other is 'vibrating' backwards. The result is that the woofers' output 'cancels' one another and results in reduced perceived output (which in the case of woofers, is bass).
In much that same way, the subwoofer can be 'out of phase' with the front speakers. And the result is the same; reduced bass. Since your sub is most likely wired with an RCA cord, flipping or reversing the wires is not possible without rebuilding the cable. So, your sub has a switch which will do the exact same thing. Without getting too technical about it, what you want to use is the setting that provides the most bass output, all other settings aside, at your 'sweet spot' (where you normally or most often sit). So, put on some music that you are familiar with that has a steady bass beat, set the volume at an average level, sit in your 'sweet spot', and have someone switch your phase switch back and forth for you. You may want to try this with a few CDs. If you can't tell a difference, then use either setting. Otherwise, use the setting that provides the most bass output. But be careful. If your subwoofer's output is set too high, you may find the setting that's out ot phase to sound "better" to your ears. Still, what you want is the setting that provides the most bass output. So find that setting, THEN readjust the sub's output to your liking.
If you have an SPL meter and you want to get more technical about setting the subwoofer's phase properly, what you want to do is figure out which setting provides the most output at your receiver's crossover setting. So, if your receiver's crossover is set to 80Hz, what you first need is a pure 80Hz tone on a CD (or DVD). Place the meter at your 'sweet spot' or where you normally place it when you calibrate your system with the meter. Playback the tone that corresponds to your receiver's crossover setting. The tone will be played back by both the subwoofer and your front speakers. Measure the tone's output level with both your phase settings (0° or 180°). The setting that produces the most output is the correct setting.