8
Model 224, 334 and 444 SB Powered Subwoofer
Placement and Operation
If you decide not to use an SPL meter try to set all the speaker levels the
same using the Test Tones. Of course, this will be much more difficult
without the meter, especially for the subwoofer.
Figure 6
Front Panel Variable Level Control located behind the removable grille
Placement and Operation
Generally speaking, the best location for your new subwoofer is the front
of the room, close to a corner (Figure 5). Every room has its own unique
sound characteristics, and flexibility in the exact placement of the sub-
woofer is always desirable. The closer the subwoofer is placed to a wall
and especially a corner, the more and deeper the bass response you will
hear. Because of an acoustic phenomenon known as "room gain," a well-
designed wubwoofer playing in an acoustically-favorable room may well
deliver low bass deeper than its rated response. However, in some rooms,
corner placement can produce a “one note” boomy effect. Under such
circumstances the subwoofer may work better away from the corner.
Experiment to find the best position in your room.
HELPFUL HINT:
A particularly useful experiment is to place the
subwoofer right at the prime listening position (move your couch
or chair out of the way and put the sub in its place). Then play
something with good bass content (preferably music), and walk
around the room, listening to the subwoofer’s response. When
you locate an area that has an ample amount of well defined bass,
you’ve found a good place to locate the sub.
Figure 5
Typical arrangement for a single subwoofer in a home theater.
1.
Start here
2.
Move to
corner for
more bass
3.
Move away
from wall for
less bass
System Set Up
When setting up a complete home theater we strongly recommend that
you use a Sound Pressure Level meter. Radio Shack® has a good one
that is very affordably priced (approximately $50). To use this meter,
turn on your system, put the Processor/Receiver in the Test Mode and
set its main volume control to 0dB. Sit in the prime listening position, set
the SPL meter to the 70dB scale, Slow Response, and C Weighting. Now,
holding the meter pointed up and in front of you, let the system cycle its
test tone from speaker to speaker and set every speaker to 75dB using
the individual level settings in the Processor/Receiver. As tempting as
it may be to set the subwoofer and/or surround speakers higher than
75dB, listen again after calibration and see if you can acclimate to these
levels. Try watching several different movies and keep in mind that the
goal is to have a system that sounds like you’re actually “in the movie.”
When using the latest discrete digital electronics which include internal
level controls for all channels, we recommend setting the front mounted
Level Control to its Preset position and using the Processor/Receiver’s
built-in subwoofer level control.
Subwoofer Tuning Without an SPL Meter
or Test Tones
Start your listening with the subwoofer Crossover control set at around
100Hz or in the Bypass position if you’re using a THX Certified proces-
sor or one with a built-in crossover. Set the phase switch to Normal, and
the front panel variable level control (Figure 6) to the Preset position.
Play some music that you know has good bass content, and turn the
level control up until you just start to hear the subwoofer working. Now,
from your normal listening position, determine whether the subwoofer
is playing loudly enough and filling in the bass frequencies of the music
evenly. If adjustment is necessary, start by changing the setting in the
processor or with the sub's level control if your processor lacks a sub-
woofer level adjustment.
If the bass seems too ponderous, boomy, or heavy, no matter how you
set the level, try moving the subwoofer away from the wall/corner. If
the bass seems too thin, try moving the subwoofer closer to the wall/
corner. Small differences in positioning can make big differences in bass
response. When you find a position that seems to work well, try switch-
ing the phase switch between its two settings, listening particularly to the
transition from the subwoofer to the satellites.
How Much is Enough?
Sometimes people prefer more bass impact for movies. Using the movie
setting for music can result in overpowering and unnatural bass repro-
duction. You may wish to determine both a video level and an audio level
if you find yourself falling into this camp. Remember however, the most
common error people make when setting up their system is to play the
subwoofer (and surrounds) too loudly. Of course, the Home Theater
Police will not arrest you for this act. But should you desire the most
accurate overall reproduction, a well balanced sound from deepest bass
to highest treble is the best way to get it. Have fun. Experiment. Enjoy.
Indicator LED
Recess and indicator for
level adjustment
Preset Position
