JL Audio e112 Owner's Manual page 16

Phase Knob
The "phase (deg.)" control knob allows the user to adjust the timing of the
subwoofer output relative to the main speakers. The "phase (deg.)" control will
primarily affect the small frequency range around the crossover point between
your subwoofer and satellite speakers. The "phase (deg.)" control's degree labeling
is referenced to 80 Hz, since this is the most common crossover point between
satellite speakers and a subwoofer. Phase settings between 0 degrees (full counter-
clockwise rotation) and 280 degrees (full clockwise rotation) are possible.
Speaker, subwoofer, and listening seat positions vary greatly in home theater
installations. Since physical positioning of speakers relative to the room
boundaries and each other greatly affects the perceived quality of sound output,
sometimes it is helpful to delay the subwoofer output. This is exactly what occurs
when you turn the "phase (deg.)" control beyond 0 degrees.
Once your E-Sub has been placed in your listening room to give you the
smoothest overall sound, and after you have determined the optimum "Polarity"
switch position (see preceding section), experiment with the position of the
"phase (deg.)" control. Using familiar source material with good mid and upper
bass content, adjust the "phase (deg.)" control and listen for better defined mid-
bass and a smoother transition between the subwoofer and satellite speaker
systems. If no single setting sounds better than another, leave the "phase (deg.)"
control at 0 degrees.
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