Alto Professional ACOM2 - Manual (Page 7)

7
Gain Reduction Meter
This 12-LED meter on the front panel indicates the amount of gain reduction in real time.
Limiter Section
The attack time determines how fast the compressor reacts to a signal above the threshold. To avoid
"clipping" the signal, we recommend using a longer attack time for low frequencies and a shorter attack time
for high frequencies. When mixing a source with a wide range of frequencies, choose a setting that will
benefit the lower frequencies.
The chart below illustrates how the Smart Gain Control (SGC) limiter works. The curve in bold is the output
signal and the dashed curve above it is the input signal. The area between the two is the amount of gain
reduction. The limiter will turn on when the signal exceeds the threshold for more than 15 microseconds. One
second after the signal is below the threshold again, gain reduction will return to 0 dB and, in this case, input
and output signals will be identical again.
GAIN REDUCTION
dBu
Hard Knee
1:1
2:1
4:1
10:1
Input/
dBu
-10 -5 0 +5 +10
0
-5
-10
Level Peak Limiting Program Limiting
Release Threshold
Input
Output