Filter
Top Products
Page 7
4.0 Operation
The XLogic Multichannel Compressor unit is a 2U rack-mounting six-channel compressor designed to provide
extremely flexible control over a 5.1 channel mix, or to be used as two separate compressors when working on
stereo material. The compressor design is very similar to that found in the XL 9000 console centre section, but
with additional controls to provide the flexibility that modern 5.1 productions require. The signal path is
balanced and DC coupled through out: this ensures extended bandwidth, low noise and low distortion.
5.1 mixing presents a number of challenges to the engineer that are not present when working in stereo. This is
essentially because the signal content can vary hugely between speakers - both in level and frequency content –
unlike stereo material where the two channels are normally similar in both level and content. This presents a
number of potential problems including:
• The LFE channel will almost certainly require different attack and release times and different thresholds
from the other channels.
• Depending on the material you may or may not want some channels to be compressed.
• Conversely you may want some channels to be compressed but not to contribute to the overall
compression.
• You may want channels to have different thresholds.
• With five speakers it is possible have signals panned so that they are the loudest signal in the room but
not the loudest signal in any one speaker.
The XLogic Multichannel Compressor is designed to give the engineer a flexible but easy to use set of tools to
deal with all these potential problems – and hopefully those we haven’t thought of yet.
4.1 Compressor Controls
The compressor sidechain controls
are straight forward and hopefully
require little explanation. The
ATTACK, RELEASE and RATIO
controls are six position switches:
the THRESHOLD and MAKEUP
GAIN controls are continuously
variable.
The compression meter at the left
of the unit normally displays gain
reduction for the Main (upper)
compressor. Pressing the LFE/STB switch shows the gain reduction for the LFE (lower) compressor.
4.2 Side Chain Adjust Section
The side chain adjust section is the key to the operation of the XLogic Multichannel Compressor. It
provides very flexible control of the compressor side chain.
S-CHAIN TRIM controls – These allow the contribution of their
respective channels to the side chain to be adjusted - effectively
allowing different thresholds to be set for each input. They are
indented at the ‘2 o'clock’ position (which is marked ‘0’) to allow
the trims to be easily set to the same level. When fully clockwise
they increase the side chain level by 10dB – effectively reducing
the threshold on that channel by 10dB. Turning a trim control
fully anti-clockwise removes that input from the side chain
completely.
An example may help: imagine the mix you are working on has
a number of loud sound effects in the surround channels. You
want the surround channels to follow the same compression as
the front channels, but don’t want the sound effects to compress the front channels. To achieve this simply
turn the side chain trim control on the Surround channels anti-clockwise.
MAKE-UP
0
RELEASE - SRATIO
2
4
ATTACK - mS
.1
.3
1
3
10
30
THRESHOLD
-20 +20
1.5
5
10
3
LFE/STEREO B
IN
0
4
8
12
16
20
dB
COMPRESSION
LFE/
ST B
METER
.2
.4
.8
AUTO
1.6
1
MAKE-UP
0
RELEASE - SRATIO
2
4
ATTACK - mS
.1
.3
1
3
10
30
THRESHOLD
-20 +20
1.5
5
10
3
MAIN/STEREO A
IN
.2
.4
.8
AUTO
1.6
1
+10
LEFT/RIGHT
LFE
LFE
0DB
SIDE CHAIN ADJUST
CENTRE
0
SURROUND
0
LFE
0
S-CHAIN TRIM
ISO
ISO
S-CHAIN TRIM
S-CHAIN TRIM
S-CHAIN TRIM
MAX
C
R
L
RS
LS
LINK
LFE
+10
+10
+10
0
Installation and Operation