I am not sure what this phase switch is and what I should be listening for in the change. If your subwoofer and main speakers are in phase, the woofer cones on the subwoofer and the speakers will move forward and backward in sync at the subwoofer crossover frequency. So, if your receiver's crossover is set to 80Hz, what you first need is a pure 80Hz tone on a CD (or DVD). A good thing to think about is if you have two subs facing each other, the waves would be hitting each other and be destructive. They'll reinforce each other's output. Most subwoofers have a switch on the back that’s labelled ‘Phase’, and has positions of 0 and 180 degrees. It also has a switch for the "phase" between normal or reverse? Phase is pretty important when playing with multiple subwoofer that face each other, or any speaker that faces subwoofers because you get canceling effects and other weird things. I just bought a new sub-woofer to pair with my Sharp sound bar. Do this with both speakers. If the sub and mains are out of phase, the woofer cones on the main speakers will move backward while the subwoofer cone moves forward, and vice-versa. First, reverse the connections on your main loudspeakers so that the black speaker wire goes to the speaker’s red terminal, and the red speaker wire goes to the speaker’s black terminal. 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. Subwoofers with phase settings or receivers with distance settings can help you dial in the best match between multiple speakers. But there’s a much more precise way of setting the phase control that guarantees perfect phase alignment between the subwoofer and main speakers. They'll … What this switch does, electrically, is the second easist thing to understand on a subwoofer’s wiring (the easiest is the ‘on/off’ switch). redleader. The phase does just that, it is like switching the + and - going to the woofer, if you have all your speakers IN phase with each other (what you normally want to do) then they are all pushing the air the same way at the same time, if you reverse this like you did on the woofer, then the woofer will be pushing the air at the opposite time that the other speakers are. I am very uneducated when it comes to speakers and audio in general. And of course, there's also the issue of placebo. That's good. The sub-woofer is a Sony, on the back it has knobs for Hz and the volume level.