DL231 OPERATORS MANUAL
7
Using the Expander alone
Disable the compressor by turning either the threshold or ratio anti-clockwise. Adjust the
expander as described above but use compressor release control to adjust release time.
An in-built ‘hold’ facility stabilises the expander against momentary gain reduction during
short duration decreases in the signal level.
Frequency Conscious Expansion
This is used when unwanted noise at different frequencies to that being processed
requires removal without effecting the required signal. For example, some guitar
flangers, treble boosters and amplifiers emit noise at higher frequency than that being
processed. Set the external equalisation by switching to ‘S/C listen’ and adjust to cut the
offending frequencies. The expander will then only operate on the required signal (the
spill from a nearby bass drum or bass guitar can be filtered in the same way). Switch to
‘norm’ and adjust the expander to obtain the required noise reduction.
NB
The external filter will not affect the processed signal, only the control circuitry.
Frequency Conscious Compression
This can be achieved by applying EQ to the compressor side-chain access at the rear of
the unit. Once again, a ‘side chain listen’ facility is provided to assist this operation. Set
the equalisation so as to boost the offending frequencies. Switching to ‘norm and
adjusting the compressor as necessary will result in the offending frequencies being
attenuated, but only when they exceed the threshold level. This method allows
broadband HF boost above 2 kHz to be applied to the signal before compression thus
obtaining a crisp, sharp sound. The sibilants thus created can be controlled without
affecting the basic tonal structure by boosting the side chain EQ at 7 to 10 KHz by 10 dB
or so. By the same token, ‘popping’ caused by LF boost can be controlled by applying
boost to the side chain at frequencies below 100 Hz. For best results, a parametric or
graphic equaliser should be employed because offending frequencies often occupy
narrow bands.
