Bear in mind that limiting is an extreme dynamic control action intended to prevent overload farther
down the line. Limiting may be more pleasing to the ear than clipping distortion, but it doesnt
sound good enough to be used for more than 6dB attenuation.
Using the De-esser
De-essers are used to reduce the level of certain high frequency vocal sounds like sibilance, over-
emphasized fricatives, and lip smacking. The 528Es de-esser provides control over much lower
frequencies than would normally be considered essing. The additional control range greatly
enhances the versatility of the de-esser.
Cleaning Up News Feeds
Use the de-esser to reduce unnatural high frequencies, the compressor/limiter to prevent overload,
the expander to eliminate noise, and the parametric to make the feed sound better and/or get rid of
interference (hiss, noise, extraneous sound, etc.).
1
Actualities carts that are prepared with the 528E produce an end product with better intelligibility
and improved signal to noise ratio. The object of the processing is to keep dynamic range within the
real limits of the recording equipment, to eliminate extraneous noise, and to get better sound.
Increasing Gain Before Feedback
To optimize a PA systems response for minimum feedback, tune out the feedback using the
parametric equalizer. To nd and eliminate resonances that can become feed back problems, turn
the system on, with the microphone(s) and speaker(s) in place as they will normally be used, then
follow the se quence below. Gain before feedback should increase about 6dB (perhaps as much as
15dB) with this technique.
1. Note the settings of each of the com pres sor controls.
2. Temporarily set the compressor ratio to 10:1. Increase system gain very carefully until a
feedback frequency becomes slightly audible.
3. With the bandwidth set at about .3 octave, and the cut/boost control set for about -15dB, tune
the frequency control of one section until the feedback is no longer audible.
4. Increase system gain until feedback becomes slightly audible again.
A. If its the same frequency that was heard rst, readjust the same frequency and bandwidth
controls until it again subsides.
B. If its a new frequency, repeat Step 2 using another of the EQ sections.
5. Increase gain again to nd the third most prominent feedback frequency. Repeat Step 2 using
yet another of the EQ sections.
6. Reduce system gain to normal operating levels.
Parametric EQ in the Sidechain
The parametric equalizer can be placed in the sidechain of the dynamic range processor to make
compression, limiting, or expanding action frequency sensitive. The equalizer is patched into the
sidechain, so the audio signal that will ultimately become the VCA?s control voltage can be equal-
ized before being fed to the detector circuitry (see Chapter 6 for additional information and Chapter
7 for hookup details).
To make the 528Es compressor/limiter more sensitive to high frequencies, boost the high fre-
quen cies on the equalizer. This increases the sensitivity of the compressor?s control circuits to those
particular frequencies, so the compressor/limiter responds more to those frequencies than any others
(in effect, the threshold setting is lowered by the extent that the high frequencies have been boost-
ed). Juggling the relationship between the amount of boost and the threshold setting can have the
effect of only compressing when the signal contains signi cant energy in the region boosted by the
equalizer. Likewise, cutting or attenuating certain frequencies desensitizes the compressor to those 528E
frequencies.
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ACEC
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