How to optimize subwoofer levels
It's confusing. In most home-theatre setups, your Dolby Digital/dts A/V Receiver has a menu for setting the levels of all your speakers, including an adjustment for the Low Frequency Effects (LFE) channel. This determines the strength of the electrical signal fed to your subwoofer's built-in amplifier. But there's also a volume control on your subwoofer, right?
So where do you set each control?
To keep your receiver's LFE output level from overloading the input stage of your subwoofer amplifier, and to keep noise levels below audibility, adjust the receiver's LFE/subwoofer output level to "0 dB", and leave it there. When you do your level checks, start with the sub's volume control at about the 10:00 a.m position, then use that control to set or trim your final subwoofer level. And of course you may have to vary it somewhat depending on which source you're watching or listening to—CD, DVD, VCR, or off-air TV. However, except for some bass-heavy CD or DVD programming, the sub level shouldn't require much re-adjustment.
About the Author
Alan Lofft was, for 13 years, Editor in Chief of Sound & Vision, Canada's largest and most respected audio/video magazine. He edited Sound & Vision (Canada) until 1996, when he moved from Toronto to New York to become Senior Editor at Audio magazine.
Lofft has been writing about hi-fi and video professionally for over 20 years, ever since his first syndicated newspaper column, "Sound Advice", began appearing weekly in The Toronto Star, Canada's largest-circulation daily newspaper. In the late 1970s, he became a contributing editor, columnist, and equipment reviewer at AudioScene Canada, the leading national consumer electronics magazine at the time.
He also wrote on consumer electronics for Maclean's magazine and made occasional appearances on TV on "Canada AM," the national CTV morning show, and on June Callwood's national afternoon TV talk show.
In 1983, he was appointed editor of Sound Canada magazine, which he relaunched in 1985 as Sound & Vision, incorporating video content and reviews as well as hi-fi and audio features. He also became a contributing editor to Stereo Review in New York, and an audio columnist for Music Express, a Canadian rock magazine.
An audio and electronics enthusiast from childhood, Alan began building vacuum-tube hi-fi gear for his father, who was an audiophile in the 1950s. Lofft's passion for audio continued through college, during which time he hosted and produced "On Campus", a radio show taped on location (on a portable Ampex 650 open-reel recorder) at Wilfrid Laurier University and broadcast locally in Kitchener, Ontario.