User guide

17
Configuring the Preamplifier/Processor
The MultEQ Pro application is responsible for measuring the room response and
computing the complex equalization filters for the room. The speaker type,
crossover frequency, level, and trim settings reported by the application must be
entered manually in the preamplifier/processor.
Before the MultEQ Pro Calibration
If the subwoofer has a built-in lowpass filter it should be bypassed, or set to the
THX setting. Sometimes there is an input called “LFE” that has the lowpass filter
already bypassed. This must be done before MultEQ Pro measurements are made.
If the subwoofer lowpass filter cannot be defeated, set it to its maximum frequency.
Any subwoofer gain controls should be set to their nominal settings, such as at the
THX position, or at 12 o’clock on a conventional level control. Phase controls, if
they exist, should be set to 0°.
If the subwoofer has any sort of “Auto”, “Standby”, or “Sleep” mode that turns the
power to the subwoofer off after it does not receive any signal for some period of
time, disable this mode. This will ensure that the subwoofer is always on and ready
to output the MultEQ test signal. Failure to disable this mode could chop off the start
of the test signal and this would result in inaccurate subwoofer measurements.
During the MultEQ Pro Calibration
The Audyssey Sound Equalizer not only performs room equalization, it also
measures various parameters that must be set within the preamplifier/processor so
that the playback system is calibrated. MultEQ Pro measures the distance from
each loudspeaker to the primary microphone location (or position 1), the
recommended optimum crossover frequency for each channel to the subwoofer, the
level trim for each loudspeaker channel, and the absolute polarity of each
loudspeaker.
Consult the manufacturer’s documentation of the preamplifier/processor on how to
manually set the parameters reported by the MultEQ Pro application in the
Detection Results Page (page 27)
Defeating the lowpass filter
in the subwoofer ensures
that the MultEQ Pro
software has the best
possible chance of
producing the smoothest
response through the
crossover region because
the only filter to be applied
is the one in the bass
management system of the
pre/pro.
The crossover frequency in
surround controllers often
defaults to 80 Hz. MultEQ
Pro examines solutions
across a range of
frequencies to optimize the
match between subwoofer
and satellites both in
magnitude and in phase.
This often results in a
different recommendation,
but results in a smoother
amplitude and phase
crossover blend.