A:Answer There are a couple of different ways to go about tuning your subwoofer for optimal settings (ultimately it will be personal choice and taste)!
If you have a receiver/amplifier that features an auto-calibration (this is the where you set up the included mic and each speaker in the setup produces test tones to determine the receiver levels), then you will want to set the GAIN at the halfway or 12 o'clock position and the Low-Pass dial to the "LFE" value (all the way clockwise).
If you would like to set the subwoofer's crossover yourself, then you will want to set the GAIN at the halfway or 12 o'clock position and the Low-Pass dial around 80-100Hz.
For the On/Auto/Off switch, if you set the switch all the way up, then the subwoofer will always remain ON. If you set the switch to the MIDDLE position, then the subwoofer will turn on and off with your receiver/amplifier.
Lastly, the phase switch controls the polarity of the frequencies outputted. If you have 2 subwoofers in your room/theater that are facing each other, put one at 0 degrees and the other at 180 degrees so that they don't cancel each other's frequencies out.
