Drawmer LX20 Dual Expander Compressor - Manual (Page 7)

LX20 OPERATOR’S MANUAL 5
OPERATION
EXPAND This is the threshold control for the expander. Signals below the
threshold level are attenuated, the lower the level, the greater the attenuation. The
attack time is preset at 2mS and the release time is linked to the release time of the
compressor.
The LED above the EXPAND control indicates the onset of expansion. A switch is
provided at the anticlockwise position, which disables the expander when it is not
required.
COMPRESS This serves as the input gain control to the compressor which has a
preset threshold. Simply rotate clockwise until the required amount of compression
is achieved. The amount of compression is indicated by a LED bar indicator on the
front panel. With a signal at system level , setting COMPRESS at #3 will just begin
to compress the signal. 40dB of gain is available which will enable low level signals
from guitar or some non-electrical keyboards to be amplified and compressed in
one operation.
ATTACK The speed at which the compressor responds to a rise in signal level is
adjusted by the attack control. The sound of any percussive signals can be altered
to some extent by using this control because long attack times allow the initial part
of the signal to escape compression thus giving a certain amount of ‘punch’ to the
sound. Setting this control at the mid-position is a good starting point, further
adjustments being made as required.
RELEASE When the signal drops in level , the compressor must recover, ready to
accept the next signal peak. The speed at which it does this is governed by the
RELEASE control. The faster the release, the louder the apparent output level, but
most compressors create some distortion when short release times are used, so
care should be taken to arrive at the correct setting. Once again, the mid-position is
a good starting point. The final setting will depend on the nature of the signal in
relation to the final result and individual taste. NB Small amounts of distortion
caused by a short release times can have pleasing effect on some signals (e.g. Bass
guitar) but care should be taken to ensure the distortion does not become excessive
otherwise the results are unpleasant.
OUTPUT With the LX20, increasing compression also increases the output
level, which is then adjusted by the output control to compensate for the increase.
A simple LED array gives indication of signal levels in volume units (VU). This
enables the output to be adjusted to the required level.
BYPASS This switch allows comparison between the input signal and the
output. With input at system level the output is adjusted to the same reading on the
VU meter. It should be remembered that if the input is a low level signal,
comparison between input and output serves no useful purpose. This switch is only
of value when input and output are at a similar level.
STEREO LINK When a stereo signal is being compressed, the stereo link
switch is used to prevent image shifting caused by different signals appearing on
each channel. In this case, the controls of each channel must be set the same.
It is also possible to use the LINK for special effects. For example, if a mono
backing track is fed to one channel which is set to unity gain (Compress control set
to #3) and a vocal track to the other channel with 'Compress' set to, say -6, when
the vocal compresses, the level of the backing track will drop. Subsequent mixing of
the two tracks will result in the backing being attenuated every time a vocal is
present.