The phase control in a powered subwoofer allows the user to add electrical delay to the incoming signal. The phase control operates over a range of 0 to 180 degrees. Adding delay to the subwoofer signal can sometimes help the subwoofer to integrate better with the loudspeakers in the room. Setting the phase control to 180 degrees reverses the polarity of the subwoofer. In some application where the subwoofer is placed on a wall opposite from the speakers, reversing the subwoofer polarity can yield better in-room low frequency response. When you reverse the polarity of a subwoofer, the subwoofer’s driver moves inward while all other speaker drivers in the system are moving outward.
All SVS subwoofers feature a continuously variable 0-180 phase control which allows the most complete range of adjustment in small increments to achieve the best sound possible. Other brands of subwoofers may only offer a simple 0/180 phase switch (also referred to as a polarity switch), which not as useful as a true variable phase control.