TL Audio 5051 - Manual (Page 18)

Stereo linked compression is essential to avoid imbalances in the stereo
image (known as “dips”) to appear on one side of a stereo signal, if the signal
exceeds the threshold on that side only. If a compressor has not been stereo
linked, the “dipping” of one channel can sound very obvious and unnatural. In
linked mode, if either signal crosses the threshold setting, both channels will
react together and will be compressed by the same amount. For best results,
both channel settings should be made the same to maintain a consistency
over the stereo image.
A variation on this is when two units are used to perform Ducking or Gating,
where the gain of one 5051 is controlled from another, but without reciprocal
action. This is useful where one 5051 is used to reduce the gain of
background music when the microphone signal is present, for example. The
link cable should be fitted, as for stereo operation, but the Link switch should
only be engaged on the ‘slave’ 5051 (the background music channel in the
example above). If the compressor is switched out on the ‘master’ unit, gain
reduction will only occur on the slave unit. The threshold and ratio controls on
the master 5051 will determine the amount of compression performed by the
slave.
4.20 Equalisation.
The 5051 equaliser section has four bands, each with a continuously variable
cut and boost control. Each band has a four position switch to select the
nominal corner frequency for the shelving bands (LF and HF), or centre
frequency for the peaking mid bands (LM and HM). The Q (or bandwidth) of
the equalisers is approximately 0.5 (2 octaves), giving a broad effect and
allowing a good degree of overlap between bands. Remember that there is a
good deal of gain available from the EQ section, and greatly boosting one or
more bands can cause the red Peak LED to illuminate as the 5051 is driven
towards clipping. In this case you need to compensate by bringing down the
5051 output level control until the Peak LED is extinguished.
4.21 LF Band.
The LF (Low Frequency) band of the equaliser has a shelving characteristic -
i.e. it extends from the selected frequency to the extreme low frequency limit
of the equaliser’s response.
The corner frequency of the LF band is selected by a rotary switch from 60Hz
to 500Hz, and the cut or boost is controlled by a continuously variable, centre-
detented rotary knob. At the selected corner frequency, up to 12dB of cut and
boost are available. The slope of the shelf is 12dB/octave, and typical
response curves are shown in the specification section of this manual.
4.22 LM
Band.