15
Owner’s Manual
Owner’
s Manual
Matrix, Compressor, and Metering Section
tantly, auto-gain compensation that provides the ap-
propriate amount of makeup gain based on the amount
of compression taking place.
The following knobs and switches are used to control
the compressor.
36. THRESHOLD
Determines the level at which the compressor begins
to act on the incoming signal. It is calibrated in deci-
bels, ranging from –30 to +10 dB.
37. RATIO
Determines the change in output level as a function of
the change in input level, once the threshold has been
exceeded. The Ratio control ranges from OFF (1:1) to
LIMIT (
∞
:1). Thus, if the ratio is 2:1, an increase in
input level of 10 dB (assuming the input is above the
threshold level) results in a 5 dB increase in output level.
When set to LIMIT, the compressor acts as a peak
limiter. After the initial attack time, the output changes
very little once the input crosses the threshold.
32. MATRIX A and B Input Controls
The Matrix A and B controls allow you to create sepa-
rate mixes, or a stereo mix, from Groups 1 through 4 and
the Left and Right Mix outputs. Simply adjust the six
matrix input controls to create the mix you want at the
MATRIX A or B outputs.
33. MATRIX A and B MASTER Controls
Use these controls to adjust the overall signal level at
the MATRIX A and B outputs.
34. AFL Solo Switch
The AFL switch allows you to hear the Matrix signal
through your headphones or monitor outputs. This
comes after the MATRIX MASTER, so you can hear the
relative signal level of each Matrix output.
When you engage the AFL switch on both MATRIX A
and B, the soloed signal appears in stereo in the head-
phones and monitor outputs. This is useful when you
want to use both Matrix outputs to create a stereo mix.
Remember, PFL solo mode always overrides AFL solo
mode. If you engage a PFL solo switch on a mono or
stereo channel, the AFL solo is disconnected from the
headphones and monitor outputs and replaced with the
PFL signal. The Rude Solo LEDS below the SOLO meters
indicate which solo mode is active.
35. COMPRESSOR/LIMITER
A compressor is used to reduce or limit transient
peaks in a signal. As the input level to the compressor
increases, the output level from the compressor increas-
es linearly until the threshold point is reached. After
that point, the output level no longer increases linearly.
Instead, it increases at a reduced rate determined by
the ratio setting. In other words, the greater the ratio
setting, the less the output level changes as a function
of the input level.
A compressor is often used on an individual signal
(voice) or group of signals (drums) to smooth out tran-
sients and allow signals to sit in the mix without harshly
cutting through. A limiter, on the other hand, is often
used between the mixer and the amplifier(s) to avoid
power amplifier clipping or overdriving the speakers,
known as system limiting.
The Onyx 4•Bus design team decided the compres-
sor/limiter functions could be carried out onboard using
a new integrated analog stereo compressor/limiter chip
designed by THAT Corporation. It provides threshold,
ratio, fast/slow attack control and, perhaps most impor-
RUDE
SOLO
PFL
AFL
PHONES
12V, 0.5A
LAMP
POWER
PREMIUM ANALOG MIXER
w / P E R K I N S E Q
MONITOR
MAIN MIX
O
O
MAX
O
O
MAX
O
O
MAX
O
O
MAX
O
O
MAX
O
O
MAX
20
15
10
6
3
0
2
4
7
10
20
30
LEFT
RIGHT
0dB=0dBu
LEVEL
SET
CLIP
CLIP
COMPRESSOR
MATRIX
A
1
2
3
4
LEFT
RIGHT
O
O
+15
O
O
MAX
O
O
MAX
O
O
MAX
O
O
MAX
O
O
MAX
O
O
MAX
O
O
+15
MASTER
B
PHONES
O
O
MAX
O
O
MAX
O
O
MAX
O
O
MAX
SOLO LEVEL
TB ASSIGN
STEREO
MAIN
TO MON
FAST
ATTACK
BYPASS
COMP
20
15
10
6
3
0
2
4
7
10
20
30
1
2
3
4
5
6
7
8
9
10
12
15
INPUT
G.R.
0dB=0dBu
AUX
1-2
AUX
3-4
AUX
5-6
MAIN
MIX
AFL
AFL
COMP
ASSIGN
GRP
GRP
GRP
GRP
MONO
TALKBACK
O
O
MAX
5:1
1.5:1
2:1
MAIN
MIX
OFF
GRP
3-4
GRP
1-2
THRESHOLD
+10
0
-10
-20
-30
LIMIT
OFF
RATIO
