Sound Reinforcement - Lexicon Prime Time 93 Owner's Manual

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levels of the delay functions into the INPUT MIX, and mix some of the input
into the OUTPUT MIX. In general an effect can be spatially enhanced by using
the INPUT MIXER OUT as the left channel and the MASTER OUTPUT as the right
channel (or vice versa). A proper balance between the two can be made by
adjusting the OUTPUT MIX MASTER control.
In addition to synthesizing stereo, M.93 can be used to enhance a stereo
source with spacious ambiance: the output can be mono, stereo, or syn-
thesized quad. Bring the left channel of a stereo source to the INPUT and
the right channel of a stereo source to the AUX INPUT. Set up an input mix
predominantly of IN, a smaller amount of AUX, and recirculation from delay
taps A and B. Use an output mix predominantly of AUX with a smaller amount
of IN, phase inverted, and the delay taps A and B. Take a mono output from
the MASTER OUTPUT. For a stereo output use the INPUT MIXER OUT as left and
the MASTER OUTPUT as right. To make quad, use DELAY A and B outputs for the
rear channels. An alternative approach for quad is to use the original source
for front channels and the stereo outputs of M.93 for the rear channels (either
INPUT MIXER and MASTER or DELAY A and B output pairs). (The DELAY A and B
outputs are likely to be superior for rear channels because they do not con-
tain any direct source which might lead to confusion in localizing the sound.)
3.6 SOUND REINFORCEMENT*
If a sound comes from two different sources but one delayed 40 msec or less
with respect to the other, then the sound will appear to be coming from the
first (earlier) source and not the second (providing that the second is not
more than 10 dB louder than the first). This is called the
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precedence .. effect
and because of it amplified sound in a hall, sufficiently delayed, seems not
to come from the amplified source but from the real source. Since sound travels
one foot in about .9 msec, delaying an amplified source by 1 msec for every
foot that it is from the real source insures that sound from the real source
reaches the listeners first. M.93 provides two independent delays from DELAY
A and B outputs which can be used for sound reinforcing speaker systems at
two distances from the source. In this application M.93 is used as a simple
*Klepper, David L.,
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Application of Digital Delay Units to Sound Reinforcement
Systems
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,
Lexicon Application Note: AN-2, 1975.
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