µ-Dimension Glow DSP8 Instruction Manual page 45

Adjusting the actual signal delay can be accomplished in several
manners, similar to adjusting equalization. Often, the processor
manufacturer's instructions will provide a good set of guidelines to
follow when tweaking their products. What will be presented here
are general guidelines and considerations to make the job easier.
The tools you can use to help tweak the signal delay include all of
the frequency response measuring tools; an RTA, a Time-Energy-
Frequency analyzer, etc. But as always, the most valuable tools in
the arsenal are your ears!
If the processor manufacturer has specific tuning techniques spelled
out in the product manual, use it first. If that yields acceptable
results, then you're almost home free. Regardless of whether or not
you use the manufacturer's recommendations, you should use the
available tools to verify the results.
An RTA can be used for tweaking delay in essentially the same
manner as for equalization. In fact, while tweaking delay, you will
likely find that also tweaking the EQ, and possibly the crossover
also, will yield the best overall results.
Before adjusting the signal delay on any speaker, study the speak-
ers as installed, and determine which speaker is probably the
closest to the listener, which is next closest, etc. Using a tape
measure is not the most accurate tool, but it can get close enough
for determining approximate path lengths from each speaker to the
listener's ears. When measuring this way, try to approximate a
measurement from the center of the speaker's voice coil to the
listener's ear. The center of the voice coil is a closer approximation
to the acoustical center of the sound produced by a speaker than the
front of the speaker cone, or any other point on the speaker. (The
actual acoustic origin varies for every speaker, relative to frequency
and output level.) Write down all of the estimated path lengths, and
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