Ashly DPX-100 Operating Manual page 13

Operating Manual - DPX-100 Graphic Equalizer - Compressor/Limiter
accelerate again, distorted operation requires an instant acceleration, instant stop, a
change of direction, and instant acceleration again.
Since speaker diaphragms are subject to the laws of physics, they won't take this
kind of punishment for long. The diaphragm may shatter, or its voice coil may overheat. In
addition to the damaged caused by sustained overload, the speaker may also be
damaged by occasional, one-shot high level overload, for example, the sound of a
microphone falling face-first onto a hardwood floor. Even if this type of transient doesn't
destroy a speaker outright, it may damage the speaker surround in such a way as to cause
mechanical abrasion and future failure.
Alternatives For Sound Installations
To install a compressor/limiter in a sound system using a passive crossover, insert it
between your mixing console output and the power amplifier input. For systems using
electronic crossovers, there are two ways to use a compressor/limiter. It may be inserted
between the mixer output and the crossover input, in which case it will act on the entire
audio frequency spectrum. Alternately, if the limiter is inserted between an output of the
electric crossover and the input of a power amp, it will only affect a specific band of
frequencies.
Recording
The Ashly limiter can be used to prevent tape saturation in analog recording. Also,
with modern trends toward inexpensive digital recording, it remains necessary to protect
against input overload. With digital recording, the information stored on tape, hard disk,
optical disk, etc., is either a 1 or 0, so actual signal level on the tape is not the concern it is
with analog recordings, in fact it is not even a user controllable parameter. What is of
concern however, is the signal level applied to the A-D(analog to digital) converters. If
clipping occurs at the converter input stage, the resulting distortion is most unpleasant,
and will be recorded digitally as if they were part of the original audio signal, forever mixed
with the audio. To prevent converter distortion while preserving the extended dynamic
range of digital recording, look up the max input level of your recorder/converter and set
up the limiter as follows:
1. Set Gain to 0.
2. Set Threshold to 2-3 dB below max converter input.
3. Set Ratio to 10.
4. Set Attack to 2 mS.
5. Set Release to 0.2 Sec.
6. Set Output level to 0.
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