and the listening seat. Moving either of these even a few inches is sometimes
enough to cure—or create—an intolerable sound. The only way to find out what
works best is by experimentation.
With full-range speakers, the range of places you can put the speakers and still
get proper imaging may be fairly limited, and some of these positions may
result in standing waves that can’t be tamed. Things are more controllable
through the use of a subwoofer or two. Positioning of the bass speakers has
almost no impact on imaging, so a subwoofer can be located with only standing
waves in mind.
Subwoofer Placement
There is no argument among audiophiles that the loudest bass output from a
subwoofer comes from corner placement. The natural megaphone-like flaring
outward of walls from a room corner focuses low frequencies—giving them no
place to go but toward you. In the case of subwoofers, there is no automatic
penalty in overall balance for this maximal bass, since your main speakers can
be located elsewhere. It still may be too much bass for your room or (more par-
ticularly) your favorite listening spot in the room, but unless you are seated in a
“null” spot, where sound from the sub is cancelled or diminished by out-of-
phase reflections from elsewhere, there should be plenty of bass from corner
placement.
If you are seated in such a null spot, your only real choices are generally to
move either the subwoofer or your listening position until bass returns to the
point that satisfies. Cranking up the level control or changing the crossover
point almost certainly won’t help much. But flipping the phase control 180
degrees sometimes may make a difference, especially if the null is a product of
cancellations caused by interaction with low frequencies from your main speakers.
If you are in the opposite sort of situation, where direct and reflected bass
waves converge in phase and produce a strong peak at your listening location,
you can—if you like—deal with that both with changes in placement or in the
position of your sub’s level control (or, less likely but possible, the crossover
frequency chosen). We say “if you like” because there is no such thing as too
much bass for some listeners, and we don’t want to be dogmatic. You are defi-
9
Most bass output; least even
bass response.
Moderate bass output; more
even bass response.
Lowest bass output; most
even bass.
PSB subwoofer
PSB
subwoofer
PSB
subwoofer
