Duende User Guide
Page 23 of 29
Compressor/Limiter
Introduction
The Channel Compressor/Limiter Section has a number of key features including a variable
compression ratio from 1:1 to Infinity:1, a variable threshold from -20dB to +10dB, auto sensing
attack time (or selectable 1ms attack time), and a variable release from 0.1 to 4 seconds.
The Compressor/Limiter has two modes of signal detection, Peak and RMS. As their names
suggest these modes of detection either act on peaks of the incoming signals or on their RMS or
average levels. This gives two very different modes of compression and limiting with Peak Mode
giving far more dramatic compression characteristics.
Detailed Parameter Description
RATIO:
When turned to 1:1, the Compressor/Limiter section is inactive. Turning the control
clockwise increases the compression ratio to give a true limiter at the fully clockwise position.
The compressor normally has an ‘over-easy’ characteristic. Selecting ‘PK’ changes this to peak
sensing, and replaces the ’over–easy’ characteristic with a hard knee, providing an alternative for
some instruments.
THRESHOLD:
Whenever a signal exceeds the level set by this control, the compressor will start to
act at the ratio set by the RATIO control. This control also provides automatic make-up gain, so as
you lower the threshold and introduce more compression, the output level is increased,
maintaining a steady output level regardless of the amount of compression.
RELEASE:
Sets the time constant (speed) with which the compressor returns to normal gain
settings once the signal has passed its maximum.
FAST ATT:
Provides a fast attack time (3mS for 20dB gain reduction). When off the attack time is
program dependent (3mS – 30mS).
The yellow and red LEDs, on the bottom of the LED display area, indicate the amount of gain
reduction (compression).
Expander/Gate
Introduction
The gate/expander section contains a number of useful features including a variable range from 0
to 40dB, a variable threshold from -30dB to +10dB, a fixed attack time (switchable to Fast Attack of
