More About Sidechain Eq - dbx DDP Manual De Operador

Section 4: Editing/Saving/Recalling Programs
TSE mode: Dark, Warm, None, Light, Bright: There are five TSE™ Tape Saturation Emulation settings in the
DDP. TSE™ is tied to the TYPE IV™ Conversion process, and allows you to add definition to your recordings in
pleasing amounts of your choosing. Because TSE™ is related to the analog to digital conversion process, its set-
tings are inactive while processing a digital source. (See Appendix 1.)
Bands 1, 2, and 3: The EQ is a three band parametric. It allows adjustments of frequency center, Q, and level.
Frequency Center: (From 25Hz to 20kHz) You can choose a center frequency from 25Hz to 20kHz all three
bands of the EQ.
Q: (From .25 to 16) "Q" is a setting that corresponds to the width of the frequency band. For example, a Q of 8
or 16 will produce a very sharply pointed EQ setting, affecting very few frequencies around the selected frequen-
cy center. A Q of .5 or 1 produces a very wide range of effect around the center frequency. The effect is a broad,
smoother EQ setting.

MORE ABOUT SIDECHAIN EQ

The sidechain functions are convenient in many applications, such as broadcast engineering, where engineers are
asked to provide "ducking" functions, as well as de-essing. Frequency-specific and sustain-related compression are
also possible with the use of the sidechain functions of the DDP.
It is possible to separate certain vocals and instruments from a mix using frequency-weighted compression. With
the 3-band parametric EQ in the sidechain path, the equalization settings do not directly shift the timbre or fre-
quency response of the audio signal. They merely alter the threshold response of the processing section of the
DDP on a frequency-weighted basis.
With this arrangement, raising certain frequencies on the sidechain 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 signals will not cause compression.
During the recording of cymbals and tom-toms, a compressor with an equalizer in the sidechain path can help
prevent tape saturation. The equalizer can be adjusted for boost with a peak of about 5kHz, causing the cymbal
to be compressed on a very loud crash, stopping tape saturation at high frequencies, where there is less head-
room. 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.
This equalization in the sidechain 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 equalizer bands causes any sound with domi-
nant energy in the affected register to pull the level up because the DDP will detect a need for less compression.
To apply de-essing to vocals without using the De-Esser element, use the parametric equalizer in the sidechain cir-
cuit and set it for high frequency boost in the specific frequency range where the vocal hiss or lisp occurs (gener-
yyyyy
ally in the 4-6kHz region). This pre-emphasizes the already hissy vocal 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. While it is true that all frequencies are lowered in level
when the compressor is triggered, generally the sss sound occurs alone, before or after the dominant tone in the
voice. To hear an example of this type of setting, listen to the factory setup called "De-ess Vocal."
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