Drawmer LX20 Dual Expander Compressor - Manual (Page 8)

LX20 OPERATOR’S MANUAL 6
REAR PANEL CONNECTIONS
The LX20 is equipped with jack sockets at the rear to interface with other
equipment. Apart from input and output sockets, which are unbalanced, the LX20
has two important additional sockets which increase its versatility.
SIDE CHAIN S/R The side chain send and return socket allows an equaliser to be
inserted into the control system of the compressor, thus making the unit more
sensitive to certain frequencies and less sensitive to others. Vocals can benefit
greatly from the addition of side-chain. e.g. In order to add richness to a vocal some
HF and LF. boost may be required prior to compression. In so doing the sibilant
content (esses and t's) can become dominant and tend to spoil the effect. Also, the
bass boost amplifies 'pops' created by bursts of air hitting the microphone. In some
cases this can create a terrific thud. The side chain socket requires a stereo jack
plug where the ring is the signal send, which is connected to the input of an
equaliser. The output of the equaliser is then connected to the tip of the stereo jack.
The equaliser should then be adjusted so as to compensate for any sibilance and/or
‘popping'. Any equaliser can be used for this purpose, parametric or graphic
equalisers being the most versatile for this application. Some trial and error will be
required to achieve the desired results, but in general, boost frequencies between 3
kHz and 8 kHz by about 5dB to 10dB to compensate for sibilance (de-essing) and
boost at 50Hz to 200Hz by the same amount to overcome 'popping'. Having applied
equalisation, the compressor becomes more sensitive to the boosted frequencies,
thereby compressing those frequencies more than the rest of the audio band in this
way, the desired richness is obtained without the unpleasant side effects. This is
just a guide. The final settings will depend on the style of vocal and the individual,
but remember that boosting a frequency in the side chain will cause a reduction in
that frequency at the output
MUTE The mute socket enables the channel to be disabled when not required. This
can be via a foot switch or a control unit of some sort. Shorting the socket disables
the channel, a LED on the front panel indicated when the MUTE facility is in
operation. Now that MIDI is being used extensively, both by the musician and the
studio, the mute port can be operated by any MIDI unit which has a suitable output
socket. The DRAWMER T102 interface and M401 'MIDMAN' are two examples of
units which will control the mute socket on the LX20. When muted, no matter what
signal is present at the input the output will be silent. WHEN THE LX20 IS USED
WITH THE STEREO LINK ON, BOTH MUTE SOCKETS SHOULD BE OPERATED
SIMULTANEOUSLY.