The SVS manual though small has all the info you need regarding the knobs at the back. Here is an excerpt,
Volume/Gain
Use “gain” (in conjunction with your receiver’s subwoofer output level control) to dial in a bass calibration to your liking. Start calibration with the sub’s volume/ gain no more than 1/4 to 1/3 of the way up (turned clockwise from the left).
Crossover Frequency.
If you use your DD/DTS receiver/processor’s internal crossover to manage bass frequencies (highly recommended), the setting of this knob on the sub is irrelevant. (Note: Use the SVS’s crossover “Enable/Disable” switch discussed below to take advantage of this configuration.) Otherwise this knob is used to best blend your SVS to your other speakers. Typically used in stereo only systems today.
Phase.
Think of bass waves as conflicting or enhancing each other, depending on the timing of their arrival at your listening location (either together, or not). Since some of your room’s bass might come from main, center and/or surround speakers, as well as your sub, getting these bass wave forms to arrive in a complementary, enhancing fashion is the difficult job of the phase control. Essentially, “phase” varies the timing of the bass waves coming from the sub. But don’t despair if you don’t hear much difference with changes to the phase knob, the effect of bass cancellation will vary by volume and frequency in your room, and no single setting is likely to ever be “perfect”. One simple technique to optimize phase is to find a nice “bassy” loop (such as the menu of “Godzilla”) and measure the loop’s SPL response at various bass peaks. As the loop runs, you can have an assistant adjust the phase control. When you see the most response on a given bass passage, typically that’s the setting with the least room-induced cancellation (for the frequencies of the demo loop).
Line In/Out.
Use one of the sub’s “Line In” jacks to connect the subwoofer to the output jack of your receiver/processor. Feeding just one input is enough. If you are using a conventional amp and/or a stereo setup you can use the “Line Out” jacks to send sound (filtered of bass information) back to your system amp. A simple RCA to RCA cable is all you need.
Auto On.
Your Powered Box allows itself to be in an “auto on” mode or on all the time. With the switch in the “Auto” position your subwoofer will “sense” that a DVD or CD etc. has begun and switch on immediately (the “hard” power switch mentioned below must be on naturally). A few minutes after a movie, the auto-on light will turn red, switching the sub back off. When running (and sensing a signal) the auto-on LED will be green. Sometimes, with very low listening levels, your subwoofer might not get enough of a bass signal from your surround sound processor to “trip” the auto-on circuit. Should you ever find this to be the case you may leave this switch to “On”, or turn the receiver’s subwoofer output up, and the sub down.
Crossover Enable Switch.
If you allow your DD/DTS surround-sound receiver or processor to manage bass frequencies (recommended), this switch should be set to “Disabled”. This disables the “Crossover Frequency” knob and allows your sub to reproduce just what it’s fed from the receiver. If you use the sub in a two channel (stereo only) configuration, then “Enable” the crossover and adjust the associated knob to best blend the sub into the low frequency output of your speakers. High level inputs/outputs. Not commonly used today, but binding posts are there in case you don’t have low-level inputs/outputs on your receiver/processor. Typically utilized only if you are not using a DD/DTS compatible system.
Power.
This heavy duty two-position switch next to the power cord will completely cut the power to your sub amp. Flip this switch to off before you ever move the sub or change inputs or outputs.
A/C connection.
Plug your sub into a dedicated A/C outlet. “Convenience” outlets of typical receivers often don’t provide the needed current. Avoid them.
Fuse.
User replaceable, contact SVS if you have trouble finding one.
