The addition of FDL further improves the ability of the Leveler circuit to operate smoothly and undetected by introducing a measure of control over the different dynamic characteristics of low frequency vs. high frequency program material. By allowing the Leveler to discriminate between high and low frequency dynamics, the attack time applied to low frequency program is proportionately slower than at higher frequencies. When leveling and compression are used together, the Leveler maintains the gain platform so that compression is consistent over the varying levels of program material, providing smooth sounding dynamic compression. The leveling action is interactive between the two channels when the Leveling Link button is depressed. In this mode, one control signal preserves overall balance and stereo imaging.
Compression is accomplished with a variable ratio, attack and release.
The attack and release times are derived from and vary with program material. The DVG monitors short term and long term average levels, compares them and impedes gain changes when program dynamics might be sacrificed for arbitrary gain reduction. Vocal program material is especially benefited by this feature, allowing voices to sound natural, even under heavy compression. The DRC allows very rapid recovery from gain reduction under certain complex program waveforms. Signals that are high in peak amplitude, but low in relative power, can cause an increase in compression release rate.