562E
9
Using the Sidechain Key Input
The sidechain K
EY
I
NPUT
is a patch point in the control circuit of a dynamic range processor, which
provides access to the part of the circuitry that tells the VCA what to do. The 562E’s sidechain is
routed through a TRS jack labeled K
EY
I
NPUT
, which is located on the rear panel. This is an input
for any line level audio signal (not a DC voltage) that you may wish to use as a key signal, to
control the opening and closing of the expander/gate. The K
EY
I
NPUT
jack also functions as a
sidechain insert point, providing send and return paths for external processing of the 562E’s
sidechain signal.
To apply a key signal to the 562E, set the E
XT
. K
EY
/B
YPASS
/I
N
switch to the E
XT
. K
EY
position.
Then, connect your key signal source to the K
EY
I
NPUT
jack of the 562E. Now you can adjust the
T
HRESHOLD
and G
ATE
R
ANGE
/E
XPANDER
R
ATIO
controls for the amount of gating/expansion that you
want. You can then fine-tune your sound, using the A
TTACK
, H
OLD
and R
ELEASE
T
IME
controls, as
well as the W
INDOW
A
DVANCE
feature. A typical application for using the K
EY
I
NPUT
in this manner
would be: passing the bass guitar track through the 562E while using the line-level output of a kick
drum trigger to control the gating action.
If you want the 562E to respond more (or less) to certain frequencies in the key signal, the key
signal can be equalized to accentuate or diminish certain frequencies before it reaches the 562E’s
key input. This makes the action of the 562E’s expander/gate frequency dependent. Because the
audio signal and the control signal remain completely separate, you can equalize the sidechain
without changing the EQ in the main audio path.
To make the 562E more sensitive to high frequencies in the key input signal, use an equalizer
(graphic or parametric), inserted in the key signal path after the key signal source, and before the
562E, to boost the high frequencies in the sidechain signal. This increases the sensitivity of the
control circuits to those particular frequencies, so the expander/gate responds more to those
frequencies than any others.
Cutting a frequency creates the inverse effect, making the 562E less sensitive to the frequencies
that are removed from the control signal. The 562E provides you with overlapping L
OW
C
UT
and
H
IGH
C
UT
sidechain filters for this purpose. These filters cover the frequency spectrum from 10hz
to 40Khz. If you prefer, you can use the inserted equalizer to perform the function of cutting
selected frequencies.
Interpreting the Displays
The 562E has A
BOVE
and B
ELOW
LED’s on each channel. These are indicators to show you
whether the signal at the input to the 562E is above or below the threshold. When the B
ELOW
LED is lit, and either the ratio is set for greater than 1:1, or the range is set for greater than
zero, gain reduction is occurring. When the A
BOVE
LED is lit, the signal is above threshold,
and gain reduction is not occurring.
The 562E also has one G
AIN
R
EDUCTION
LED display per channel. The G
AIN
R
EDUCTION
indica-
tion displays the amount of attenuation, in dB, that the 562E is applying to the input signal
(how far the gain is being reduced from unity). Here’s another way of looking at this: if the
G
AIN
R
EDUCTION
display says 12dB of gain reduction, switching the unit to bypass will result in
a 12dB increase in the output level.
400Hz
40KHz
ALL SIGNALS
BELOW THESE
SETTINGS ARE
UNAFFECTED
HIGH CUT RANGE
SIGNAL LEVEL
10Hz
1KHz
ALL SIGNALS
ABOVE THESE
SETTINGS ARE
UNAFFECTED
LOW CUT RANGE
SIGNAL LEVEL
Frequency ranges of the L
OW
C
UT
and H
IGH
C
UT
sidechain filter controls.
