But what’s “too high”?? Tastes vary, and so do movie soundtracks, but
your SVS subwoofer is capable of tremendous levels of low distortion, low
frequency bass — far more than most commercial subs. Take advantage of
this, especially if you like action movies with lots of “.1” channel (LFE)
action, and give the sub a bit more “bump” during calibration. Keep in mind
too that the human ear is relatively insensitive to low frequencies. This,
coupled with the fact most folks don’t watch movies at Dolby Digital refer-
ence level (fairly loud), means raising the bass up a few dBs (relative to the
main speakers) usually yields a more satisfying movie and music experience.
What sub levels do we recommend? If you watch movies at relatively
moderate sound levels, a good start is a range of +1dB to +3dB above your
other channels (as measured with your sound meter). This means the test
tone will waiver about 78 dB for the subwoofer portion of the calibration run
(88dB with Avia). (Note: You may want to rotate the sound meter SPL
meter dial to 80dB to get a good reading with these higher levels.) Note too
that many modern surround sound receivers allow a variety of different sub-
woofer level settings, depending on the “listening mode” you are in. With
“Dolby Digital” as your “mode” use the above calibration routine. You may
well find that CD “Stereo” music calls for a lower bass settings adjusted by
ear. The above is a guide… experiment! The louder your master volume
though, the more you should back off the subwoofer’s level to compensate.
Audible distress is a sign to lower things a bit. Avoid your driver bottoming,
resulting in a loud “clack”, your warning that levels are too loud for the sub.
Location and measurement. You should take the above measurements
from your typical preferred seat for watching movies. Be advised, strong
bass levels can vary tremendously simply by moving your seat, or your sub-
woofer, a few feet. Such is the nature of long wave-length, low bass sound.
Try different locations and different levels for your subwoofer, but recali-
brate your channel levels with each move. Setting levels which are too high
(and often, too low) is the most common subwoofer setup error.
Powered Box Features. We looked the world over for the
best performing sub amp yet still affordable. What resulted is an SVS cus-
tom-designed, North American-made amp with amazing build quality, and
just the features folks with today’s digital surround sound systems need.
Volume/Gain. Use gain (in conjunction with your receiver’s independent
subwoofer output control) to dial in a bass calibration to your liking. Start
calibration with the sub’s volume about 1/3 of the way up (turned clockwise
from the left).
Phase. Think of long bass waves as conflicting or enhancing each other,
depending on the timing of their arrival at your listening location (either
together, or not). Since some of your room’s bass might come from main,
center and/or surround speakers, as well as your sub, getting these bass wave
forms to arrive in a complementary fashion is the difficult job of the phase
control. Essentially, “phase” varies the timing of the bass waves coming
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