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Digital Drive User’s Manual
N
OTE: Your goal in setting the low pass crossover is to make the crossover point (the point at
which the subwoofer meets the main speakers in terms of frequency) as smooth as possible.
A
nother big factor in smoothing this point in the curve is phase, discussed in step 17, below.
15. Now adjust the low pass crossover slope. This setting is shipped at 24 dB/octave – a
fairly steep slope to prevent the subwoofer from playing upper frequencies that might call
attention to it during normal operation. At this stage, set the crossover settings under the
column entitled SETUP. Reduce the slope if necessary and use the TEST button to return
to the EQ setup screen and observe the “system response” graph – it should be as flat as
possible at the crossover frequency and immediately to the left and right of it. Too gradual
a slope (e.g. 6 dB/octave) may produce a bump at the crossover frequency, and too steep
a slope may produce a dip.
16. You should normally not need to adjust the subsonic filter. Do so only if there are anomalies
in the very lowest frequencies that you cannot address using the normal EQ process as
described below.
17. Next adjust the phase and polarity settings. Phase is in effect a short delay in the
reproduction of the audio signal. The polarity reverses the phase (i.e. 180
o
shift).
Adjusting phase can change the dynamics of standing waves and frequency cancellations
in the room. Sometimes it may be useful to adjust the phase if there is a particularly
difficult peak or valley to eliminate, and/or your room placement options are limited. Phase
and polarity ar
e also important tools to match your subwoofer to your main speakers. Y
ou
will often see a dip or peak in the crossover frequency between your subwoofer and main
speakers. Rather than correcting this dip with an EQ, try adjusting the phase and polarity
settings. It is very common for the main speakers to interact with the subwoofer to
diminish or accent frequencies near the crossover point (since this is the point where both
the subwoofer and the speakers ar
e playing the same audio information). Don’t be afraid
to experiment to find the perfect match between your subwoofer and main speakers!