TL Audio VP-1 - Manual (Page 12)

When the signal level returns to a level above the threshold, the gain is rapidly
restored to ensure that no transient edges are lost.
The Expander/Gate is perfect for removing unwanted background noise during quiet
periods of recording. A typical example would be removing the background noise,
breathing etc that occurs between vocal phrases when miking a singer. Setting the
threshold to a low level will cause the gate to open when the vocalist sings (i.e. when
the signal exceeds the threshold), after which the input signal falls back below the
threshold again. At this point the gate closes, and any low level background noise is
muted until the next vocal phrase. A similar technique can be use on any instrument
where unwanted spurious noise needs to be removed in between phrases.
4.9 Gate
Threshold.
The Threshold control sets the signal level at which the gate starts to act, and is
continuously variable between -40dB and 0dB. Any incoming signals above the
threshold will pass through the gate unaffected, while those falling below the
threshold level will cause the gate to shut.
4.10 Gate Attack and Release.
The Attack time governs how quickly the gate opens in the presence of an audio
signal that has exceeded the threshold setting. The gate effectively fades the signal in
and ramps it up to its full value, with the attack time controlling the speed of fade-in.
The range of attack times is fully variable from 0.5mS to 10mS. The Release control
dictates how quickly the gate closes again once the signal drops below the threshold.
This works like a ramped fade-out, the release time setting the speed of the fade. The
range of release times is fully variable between 30mS and 300mS.
4.11 Gate
Meter.
A four segment LED meter indicates the amount of gain reduction that the gate is
providing, and is calibrated from 10dB to 40dB - this meter only becomes active once
the gate section is engaged. A bypass switch allows the gate to be placed in and out of
circuit, allowing easy A/B comparison.
4.12 De-esser
Section.
The de-esser stage employs high quality VCAs to allow effective but natural
reduction of sibilance, typically in vocal sources. The de-esser is effectively a
frequency conscious compressor stage, that reduces the gain of a user-selectable range
of frequencies. Sometimes sibilance can be reduced by judicious use of EQ (by
cutting the frequency at which sibilance is occurring), but other instances will demand
the use of a dedicated de-esser section.
4.13 De-esser
Depth.
The Depth control sets the degree of de-essing effect - i.e the amount of gain
reduction applied, and is variable between 0 and 20dB.