DL221 OPERATORS MANUAL
6
OPERATION
Having connected signal inputs and outputs as required, set the unit as follows-
Threshold, Ratio, Attack, Release
-
Anti clockwise
Output Gain
-
0 dB
Display Switch
-
VU
Output Switch
-
Bypass
Peak Limit
-
Off
Stereo Link
-
Off
Display
-
VU
1.
Adjust input signal level on preceding equipment to show 0 dB on display, peaking
to +2.
2.
Change output switch to ‘norm’ and display switch to GR. Adjust Threshold, Ratio,
Attack and Release to give the required compression characteristics and read the
gain reduction on the display.
3.
Change output switch to VU and adjust output gain for optimum reading on the
display.
4.
If the Peak Limiter is required, adjust output gain so that the limiter operates on
signal peaks only. It is important to remember that the peak limiter is connected
after the output gain control so care should be taken to avoid ‘pushing’ the gain
controls for more level, particularly when treating stereo signals.
5.
For stereo operation, switch in the stereo link and set up as above, making sure
that all controls are the same for both channels. GR. displays will show the same
readings, except when excessive peak limiting occurs on either channel.
6.
Set ratio and attenuation to suit the particular application. When used on a final
mix, set threshold as low as possible but above unwanted noise. Ratio should be
1:2 and attenuation at 10 to 20 dB. This will provide a gentle expansion which will
minimise drop out effects during a fade. However, drums would be better with a
1:5 or 1:20 ratio and 20 or 40 dB attenuation using a higher threshold level. For
vocals, set threshold so as to remove breath and headphone noise and set ratio
a 1:2 or 1:5 with attenuation of 20 or 40 dB.
In all cases, attack is automatic and release is controlled by the compressor.
These suggestions are for guidance only. The final adjustments should be made
to suit the particular application and conditions.
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.
