Behringer Blue Devil GX112 - Compressor; Expander; Guitar Combo

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BLUE DEVIL GX112
90-91 Compressor: Often, the signal level exceeds the headroom of signal-processing devices and therefore
needs to be limited in its dynamic range, so as to avoid distortion. This job is done by compressors
and/or limiters. Limiters abruptly limit the signal above a specific threshold, while compressors provide
for a soft control process over a wider range. The side chain implemented in this algorithm generates
a control signal that emulates a so-called soft-knee characteristic for the compression process. With
the PARAMETER control you can set the compressor threshold. EFFECT A determines the compression
ratio. EFFECT B allows you to raise the volume to adapt the compressed signal to the unprocessed
one. To achieve optimum adaptation proceed as follows: adjust threshold and ratio as required, then
compare the signal levels by switching the effect repeatedly on and off. Adapt the levels with EFFECT
B, so that there will be no audible level difference between compressed and uncompressed signals.
Use this effect to give your guitar longer sustain, or to make the attack sounds of funky guitar licks
(Chicken Scratch) clearly audible, even though the guitar signal is actually limited in level.
Preset-Nr. Effect Variation PARAMETER EFFECT A EFFECT B
90 fast Sensitivity Ratio Gain
91 slow Sensitivity Ratio Gain
COMPRESSOR
Tab. 3.23: Parameters of effects 90 and 91
92-93 Expander: All sorts of background noise and hum limit the dynamic range of the wanted signal. As
long as the level of the wanted signal is considerably above the noise floor, background noise is
inaudible: the interference signal is masked by the music. Expanders can be used to efficiently expand
the dynamic range of signals. Small signal amplitudes are cut additionally which at the same time
reduces background noise. Use the PARAMETER control to determine the expander threshold.
EFFECTA adjusts the expansion ratio, while EFFECT B drives a matching amplifier (much like in the
compressor effect 90 - 91) to adapt the level of the processed signal.
Preset-Nr. Effect Variation PARAMETER EFFECT A EFFECT B
92 Hell Sensitivity Ratio Gain
93 Heaven Sensitivity Ratio Gain
EXPANDER
Tab. 3.24: Parameters of effects 92 and 93
94-96 Guitar Combo: This effect simulates the sound characteristics of a complete guitar amp, mimicking
not only two tube stages, but also cabinet and speaker. The PARAMETER control determines the
distortion intensity, while EFFECT A adjusts the presence of the sound as the signals high-frequency
portions increase. EFFECT B controls the mix ratio.
Preset-Nr. Effect Variation PARAMETER EFFECT A EFFECT B
94 - Drive Presence Mix
95 - Drive Presence Mix
96 - Drive Presence Mix
GUITAR
COMBO
Tab. 3.25: Parameters of effects 94 through 96
3. EFFECTS PROCESSOR