This is from the SVS web site. Hope this helps.
"Make sure your receiver/processor master volume is set at "00 dB" or other easy to remember level, it will become your "reference level", one very close to that intended for home theaters by Dolby Labs. And finally, set your subwoofer amp’s volume control (if it has one) to at least half-way up to start. It’s a good idea to check the subwoofer level control of your receiver before you begin the test tones. Keep the receiver's subwoofer output control to about 25% up or lower than "0 dB" (or say -6dB given a typical receiver channel limits of –12 dB to +12 dB) . This will allow your amp to work with the cleanest signal possible from your receiver, while still leaving plenty of downward adjustment you can use from your viewing position (using the remote). As the tones start, alternating, speaker to speaker (watching your sound meter now) set each speaker’s volume to 75 dB, using the receiver’s channel controls. Not all test disks or receivers are the same when it comes to calibration tones however, the recommended Video Essentials should allow you to calibrate reference level at 75dB. Ovation's "Avia" DVD is recorded at a higher level to improve signal to noise ratios during calibration, so you need to measure instead to 85dB for all channels if you use it and not Video Essentials (discussion below, regarding a "boost" to your LFE still applies but you simply add the bump you want above and beyond 85dB, vice 75dB)."
