How to stop subwoofer bass from 'leaking' into other rooms
Audyssey's new Low Frequency Containment (LFC) processing system promises to stop subwoofer bass from annoying your neighbors.
Everyone at one time or another has been annoyed by the unpleasant bass thumps of a neighbor's subwoofer or large speakers. While midrange and high-frequency sounds are more easily enclosed by walls, low bass frequencies pass right through them. And, of course, it's not just a noise problem from neighbors; home-theater bass can disturb other family members within a house or apartment.
Methods used to isolate or restrict bass from going through walls, floors, and ceilings can get expensive, and unless recording-studio construction techniques are employed bass is hard to control. Brick and concrete are more effective than Sheetrock, but most folks aren't prepared to go that far to reduce bass boom in adjacent rooms.
Researchers at Audyssey may have a far more affordable solution at hand; they isolated the range of frequencies that most readily pass through walls and floors and developed a process to reduce the volume level at those frequencies. Audyssey's system, Low Frequency Containment (LFC), also employs psychoacoustic processing that "restores the perception of low bass," the company says on its site.
Depending on the overall volume you're listening at, LFC eliminates almost all deep bass below 50Hz, and reduces bass frequencies up to 200Hz. Please understand, Audyssey LFC isn't just a simple filter, it dynamically monitors low frequencies and engages only when it finds the offending frequencies are loud enough to annoy your neighbors. LFC works with subwoofers and large speakers and will be featured in some AV receivers soon; the user would turn LFC on only when it's needed.
Audyssey isn't claiming that LFC's bass-processing effects won't be audible, just that they will be subtle enough that you won't feel the lack of bass. I haven't heard Audyssey LFC yet--it will first appear in receivers this September. When we get them here at CNET I'll let you know what I hear. Meanwhile, I have an immediate and totally free solution to the bass problem: if your satellite speakers make a fair amount of bass on their own, turn off your subwoofer during late-night listening sessions.