Aiwa TS-WM7 Manual De Instrucciones página 6

Phase
Depending upon the room or the characteristics of the right
and left speakers, sound from the powered subwoofer may
seem unnatural or unusually loud or soft.
In this case, try changing the PHASE switch setting. Set to the
NOR (Normal) or REV (Reverse) position, whichever sounds
better.
En
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