SB4001 MANUAL V.1.2 6
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Filters (Sidechain):
The “Filter” control affects the frequencies going to the internal sidechain (In any
compressor, the internal sidechain is what controls the compression taking place).
Please note, this control does not filter the audio frequencies themselves, but rather the
frequencies that are being compressed.
High pass: 60Hz, 90Hz, 120Hz
Note: Use the HPF to tailor the amount of low frequency triggering the sidechain
detector. The filters for instance can drastically change the kick drum on a drum
subgroup or the 2 buss. Just twist until you have the desired amount of low end
control.
“Boost” & “Slope” both induce very useful predefined eq curves onto the sidechain
material, both essentially over compressing the high end, while under compressing the
low end. “Boost” offers more mid band compression than “Slope”.
Boost: Induces a 1K high shelf boost and a gentle 60Hz roll off onto the internal
sidechain
Slope:
Induces a sloped filter curve with a crossover at 1Khz on the internal
sidechain.
External “Key” Input:
The SB4001 allows the use of an external signal to trigger the compressor’s internal
sidechain, a feature not commonly found in a 500 format module. This makes for an
endless array of possibilities, limited only by one’s imagination (duck the bass guitar
when the kick drum hits! Compress the snare out of the overheads, etc).
The external signal is sent to the mono balanced front panel TRS connection, which is
engaged by the “Ext In” pushbutton switch. Some examples of usage are:
Ducking: By sending an external trigger track (i.e. kick drum or snare) the main
audio signal will only compress when the trigger track hits.
De-Essing: By sending the main audio signal to an external EQ (by use of a “Y”
splitter or other means), and then sending the eq’d signal to the “External In” TRS
connector, the SB4001 can instantly be transformed into the ultimate de-esser as well.
Stereo Mix: By branching off the Left and Right input signals to the compressor
(by use of a “Y” splitter or other means) summing these two signals through an external
means (ie via your DAW or Mixer), and then sending the summed signal to an eq and
lastly, to the “External In” TRS connector, SB4001’s compression response of a Stereo
Mix can be fully manipulated via the external eq.
