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OPERATING NOTTS
Figure 6: Frequency-Weighted Compression
With this arrangement, raising certain frequencies on the equalizer
causes them to be suppressed in the audio signal. A relatively high
THRESHOLD setting can allow normal sounds to be unaffected while solo
and very loud sounds are held back. (Of course, when compression does
occur, the level of the entire program is affected.) Depending on the
THRESHOLD setting, lower level fundamentals or harmonics will not
cause compression, and the program is not subject to the phase shift nor¬
mally caused by program equalization.
During the recording of cymbals and tom-toms, a compressor with an
equalizer in the detector path can help prevent tape saturation. The equal¬
izer can be adjusted for boost with a peak of about 5kHz, causing the cym¬
bal to be compressed on a very loud crash, stopping tape saturation at
high frequencies, where there is less headroom. However, gentle tapping
of a drumstick or brushing of the cymbal will not be held back. Assuming
the tom-tom is a lower frequency instrument and can be better tolerated
by the tape, it has less need for compression. The equalization in the de¬
tector circuit means that the compressor is not triggered as readily by a
loud tom-tom beat as by an equally loud cymbal crash.
The converse of the above EQ technique may be used: dipping the equal¬
izer bands causes any sound with dominant energy in the affected regis¬
ter to pull the level up because the 160XT will detect a need for less
compression.
De-Essing
To apply de-essing to vocals (i.e., a reduction of sibilance), use a paramet¬
ric equalizer in the level detector circuit and set it for high frequency boost
in the specific frequency range where the vocal “hiss” or lisp occurs (gen¬
erally in the 4-6kHz region). This pre-emphasizes the already “hissy” vo¬
cal input to the detector. Used in conjunction with a moderate to high
threshold and compression ratio, this arrangement greatly attenuates the
“essing” without affecting the basic sound quality or balance of the voice.
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