421 AGC Leveler

The Symetrix 421 is a wide-range AGC-Leveler, a peak limiter, and a downward expander. The 421 reduces the dynamic range of its input signal by the amount of its ratio setting. That is, if the ratio setting is 2:1, then 40 dB of input range turns into 20 dB at the output. A fast peak limiter puts an absolute ceiling on the output level so you know that peaks are held to the level that you set. A downward expander reduces the gain when signals levels fall too low to process, reducing the noise bu...