Software Instruction Manual

IQ–MSD Turbo 1.4 Advanced IQ System Software
Page 146
6.4.3 Input Compressor/Limiter Function
(Figure 6.11) The Max Gain settings you select in the Gate function should be acceptable for consistent input
levels—but sometimes the unexpected happens and an extremely loud input signal is present. The Input
Compressor/Limiter function “reins in” input signals that suddenly become too loud. If the excessive loudness of
the input signal is not transitory but is sustained, use the Auto level function to control it (Section 6.4.4).
Compress: The Input Compressor/Limiter function is turned on and off with this control.
Threshold: The Threshold control sets the level at which compression begins. A signal at this level or below
is not affected, and a signal that goes above this level is compressed.
Ratio: The Ratio control sets the amount of compression applied for every step over the Threshold. This is
commonly referred to as a “compression ratio”. For example, when a 4:1 compression ratio is applied to a signal
that exceeds the Threshold by 20 dB, the signal is attenuated 15 dB. When an infinite compression ratio (
∞:1) is
chosen, the compressor works like a limiter and prevents the level from exceeding the Threshold. Note: A 1:1
compression ratio will not affect an incoming signal.
Release Time: Any input level increase over the Threshold is compressed almost instantly. The Release
Time function controls the time it takes for the gain to return to normal when the level drops below the Threshold.
Short release times allow the compressor to respond to rapid changes in input level.
Compression (Attack Time): This feature is available for all AMB-5s but only for those SMX-6s with
version 1.3 firmware or later. (To see which firmware version your SMX-6 has, locate the white sticker above the
DB-25 serial communication connector on the back panel of the unit. Units with version 1.3 firmware will be labeled
“V 1.3”.) The Compression control can be set either “Fast” or “Slow” to control the attack time of the Input
Compressor/Limiter function.
Set the Compression control to “Fast” to cause the mixer to have the shortest attack time possible. This will be very
fast—so fast that the compressor can stop extremely sudden loud transients like the sound caused by a dropped
microphone. This is a good setting for rapid speech.
Set the Compression control to “Slow” for more gentle sound sources such as most music. When the “Slow” setting
Fig. 6.11 The Second SMX-6 Sub-block Screen