BBE MAXCOM Owner's Manual page 13

A ratio of 1:1 indicates that the output signal will correspond to the input signal i.e., there is no level change. A
ratio of 2:1 indicates that for every 2 dB increase in input level above the threshold there will be a correspond-
ing increase in output level of 1dB. A ratio of 10:1 indicates that for every 10dB increase in input level above
the threshold there will be a corresponding increase in output level of 1dB, etc. If the RATIO control is set fully
clockwise, this corresponds to a ratio of infinity:1. This means that all input levels are reduced to the threshold
point and are thus kept constant. It is worth observing that a hard or infinite-ratio limit has applications in cer-
tain specialized situations, but in general this setting is neither appropriate nor necessary as this would cause
audible side effects.
The effect of the RATIO control can be shown on a graph which plots input level versus output level. It clearly
shows that below the threshold the compressor acts purely as a linear amplifier.
• ATTACK CONTROL
The characteristics of a compressor are determined to a great extent by the attack time. This is the amount of
time that elapses before the compressor begins to attenuate the output level after the threshold point has been
exceeded.
A short attack time is required for transients such as handclaps and percussive instruments like snare drums so
that the compressor is in a position to regulate these types of peaks. With other kinds of program material it can
be advantageous to apply longer attack times. It is always recommended, however, to begin processing with
longer attack times. Whenever it is required, the time should be reduced carefully as the danger of dynamics
distortion usually increases with shorter attack times.
The attack time of the MAXCOM can be set within a range of 0.1 to 200 milliseconds.
• RELEASE CONTROL
Another feature of the MAXCOM is the release time. This determines the time that the compressor requires to
return to its unity gain after the input signal has fallen below the threshold point. The release time is largely de-
pendent on the program material. If the time is incorrectly set, this can lead to two fundamental problems:
1 - If the release time is too short, the overall volume may fluctuate when signals peak above the threshold
level and give the sound an unpleasant pumping effect.
2 - If the release time is too long, pumping and breathing side effects may occur when a loud passage is
abruptly followed by a quiet passage. The VCA increases the general volume of quiet passages which leads
to a disadvantageous tonal effect.
The release time can be set within a range of 0.05 to 4 seconds.
• AUTO SWITCH
Attack and release times are important parameters which significantly influence the quality of the dynamic con-
trol process. When the AUTO switch is engaged, the manual ATTACK and RELEASE controls are put out of
action. The attack and release times are automatically derived from the program material by means of intelligent
program recognition so that setting errors can be effectively avoided. The AUTO function eliminates side effects
such as pumping and modulation distortion.
• OUTPUT CONTROL
Because compression and limiting are both gain reduction processes, the output of a compressor/limiter is often
at a lower level than the normal operating level. This loss of level must be compensated for. A reduction in the
output level is required if the operating level of subsequent equipment is lower (for instance, if the subsequent
unity has a high sensitivity input).
• CH. ON SWITCH
The CH. ON switch activates the channel. The switch is mainly used for direct A/B comparisons, which allows a
comparison between the unprocessed and processed signal. When in the OUT position, all processing functions
on the MAXCOM are turned off. If the switch is in the ON position, the unit work as a Compressor or Limiter,
depending on the setting of the controls. Please note that in the bypass mode, the input signal is still connected
to all of the MAXCOM circuitry, so that all the required controls can be used "Dry" that is without affecting the
original signal. This, in conjunction with the GAIN REDUCTION meter, provides a powerful tool for comparing
processed and unprocessed signals prior to operating the bypass switch and going "live".
• GAIN REDUCTION METER
This meter provides a convenient visual indication of the amount of gain reduction that is taking place at any
time. If a signal exceeds the input level of the threshold point this function of the Compressor comes into play
and the GAIN REDUCTION meter shows the actual measurement of gain reduction.
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OPERATION