Symetrix 562E User manual

562E
Windowing
Expander/
Gate
User’s Guide
562E

i
Table of Contents
Chapter 1 Introduction 1
Chapter 2 Operator Safety Summary 2
Chapter 3 Fast Setup 3
Chapter 4 Front Panel Overview 4
Chapter 5 Rear Panel Overview 6
Chapter 6 The Controls in Detail 7
Chapter 7 Connecting to Other Gear 11
Chapter 8 Applications 14
Chapter 9 Troubleshooting 19
Chapter 10 Specifications 20
Chapter 11 Warranty and Service 21
Chapter 12 Declaration of Conformity 23
Rev A.02, 15 Dec, 1997
Symetrix part number 53562E0A02
Subject to change at our whim and fancy without
notice.
©1997, Symetrix, Inc. All right reserved.
Symetrix is a registered trademark of Symetrix, Inc.
Mention of third-party products is for informational
purposes only and constitutes neither an endorsement
nor a recommendation. Symetrix assumes no
responsibility with regard to the performance or use
of these products.
Under copyright laws, no part of this manual may be
reproduced or transmitted in any form or by any
means, electronic or mechanical, including
photcopying, scanning, recording or by any informa-
tion storage and retrieval system, without permission,
in writing, from Symetrix, Inc.
6408 216th St. SW
Mountlake Terrace,WA 98043 USA
Tel [phone]
Fax [phone]
Email: [email protected]
562E

562E
1
IntroductionChapter 1
Typical gate setups, such as drum miking or
cleaning up multitrack recordings, all face the
same difficulty: how to apply a precise trigger to
imprecise, organic signal sources. Much to the
frustration of audio engineers, instruments and
vocalists produce natural audio waveforms, and
nature is rarely consistent. When nature meets
machine in audio processing, the results can
sound like the snap, crackle and pop you’d prefer
in your cereal, not your audio. Most gates offer
only one solution to this problem: open faster.
While they measure performance in microsec-
onds of "how fast", Symetrix is rewriting the rules
on how to open. The dual channel 562E
WindowingExpander/Gateexploitsournewly-
developed, proprietary technology to enhance
gatingandexpandercontrol. Ultimatelythe562E
delivers unparalleled fidelity to any audio signal.
GATING:Gatesmaybeusedtocleanup
virtually any type of musical instrument or audio
sound effect, but perhaps their most common use
is on drum and percussion tracks. The 562E
employs two unique tools for detecting and
controlling these audio events.
WindowAdvanceisaproprietarysystemfor
recognizing the signal to be gated. In simple
terms, it virtually creates the impossible: a gate
that opens just ahead of the audio signal. It
creates this impression by moving the statistical
energy center of the gated signal forward in time.
WindowAdvancepermitstheusertosubtlydelay
the signal energy, centering it within the enve-
lope. Through this function, the 562E’s gate
passes the entire leading edge of the audio
waveform. It accomplishes this because the gate
opens before the signal passes through the VCA.
WindowAdvanceeliminatesthenoisesand
chopped-off waveforms created by traditional
gates that struggle to open as quickly as possible
after the signal arrives.
AutoWindowing is a processing technique that
allows the user to maintain better control of the
gate envelope parameters. Its dynamic smooth-
ing process reduces “pops” and “clicks” that can
occur at fast attack settings. These nasty noises
are typically produced by envelope edges,
overshoot and instabilities. Even gates that claim
to open within microseconds fail to recognize the
reality underlying these problems: naturally
occurring waveforms do not have consistent
leadingedges. Incontrast,AutoWindowing
derives its trigger signal from the “time center” of
the leading edge of the audio waveform. This
reduces trigger uncertainty, jitters, and attack
distortion. AutoWindowingyieldsanenvelope
that is consistent and natural-sounding. It also
increases envelope consistency by eliminating
the artificial “drop off” that occurs in most gates
at the end of the release cycle. In the 562E the
signal smoothly and continuously decreases at
the end of the release cycle, creating a much more
pleasing sound.
EXPANSION: The562Ealsopermitsusersto
have a distinctive choice between gating and
expansion. A downward expander is similar to a
gate, but the expander substitutes RATIO control
for the gate’s RANGE control. The expander is
ideal for tasks requiring more subtle control. To
all possible uses for an expander, the 562E
delivers superior performance through unique
technology. Even the 562E’s ratio circuitry is
special. The ratio automatically reverts to 1:1
when the signal approaches 25dB below the
threshold. This prevents any low level modula-
tion of the expanded signal.
For the first time, open your ears to all the clear
audio you wanted without any revenge from the
processor. Experience a quantum leap forward in
gatetechnologywiththeSymetrix562EWindow-
ingExpander/Gate.
0
TIME RELEASE TIME
1 Sec 500ms
EXPANDER RATIO
GATE RANGE
1:380
2.5 Sec4 Sec 30ms
CHANNEL 2CH2 SIDECHAIN PROCESSING
TIME(dB) ATTACK
0 60ms
GAIN (dB)
REDUCTI0N
ABOVE
BELOW
30
MAX 12
3
THRESHOLD
300ms+20 AUTO
60
OFF -40
MIN
HIGH CUT
20K
200Hz1K
50Hz 4K
OUTPUT
15Hz
KEY LISTEN
ASSIGN 20Hz
LOW CUT
40K
1K 400Hz
IN GATE/EXP. 10Hz
W/FILTER
WINDOW
ADVANCE
50ms
HOLD
CHANNEL 1
TIME GATE RANGE EXPANDER RATIO
500ms 0
HOLD
TIME
ATTACK
TIME
60ms 1 Sec
RELEASE
1:3
2.5 Sec 80dB 4 Sec300ms 50ms 30ms
(dB)
THRESHOLD
ABOVE
BELOW
0
HIGH CUT
WINDOW
30
MAX 12
20K
4K ADVANCE 3
REDUCTI0N
GAIN (dB)
-40 +20
60
OFF
40K
400Hz MIN AUTO
LOW CUT
OUTPUT
200Hz15Hz
ASSIGN 20Hz 50Hz
EXT.KEY
E
KEY LISTEN
1K10Hz
IN GATE/EXP.
BYPASS W/FILTER
562
WINDOWING
EXPANDER/GATE
CH1 SIDECHAIN PROCESSING
1K
BYPASS
EXT.KEY
CHANNEL 1 INPUT
UNBALANCED
BALANCED/
BALANCED
KEY
INPUT
BALANCED/
BALANCED
OUTPUTS
UNBALANCED
CHANNEL 1 OUTPUT
BALANCED
TYPICAL CONNECTIONS
13
SIDECHAIN
1
3
2
LOW(-)=PIN 3
HIGH(+)=PIN 2
GROUND=PIN 1
1/4"BALANCED
BALANCED
INPUTS
TIP=HIGH(+)
RING=LOW(-)
BALANCED
SLEEVE=GROUND GROUND
SIDECHAIN OUT
KEY INPUT
2
SIDECHAINSIDECHAIN
UNBALANCED
BALANCED/KEY
INPUT
CHANNEL 2 OUTPUT
BALANCED
E 562 WINDOWING EXPANDER/GATE
MANUFACTURED IN LYNNWOOD, WASHINGTON USA
UNBALANCED
BALANCED/
AC INPUT
18 WATTS
MAXIMUM
FABRIQUÉ AUX E.-U. PAR SYMETRIX INC., LYNNWOOD, WA USA.
RÉFÉREZ TOUTE RÉPARATION À UN TECHNICIEN QUALIFIÉ.
CHANNEL 2 INPUT
Front panel
Rear panel

562E
2
The information in this summary is intended
for persons who operate the equipment as well
as repair personnel. Specific warnings and
cautions are found throughout this manual
wherever they may apply.
The notational conventions used in this
manual and on the equipment itself are
described in the following paragraphs.
The lightning flash with arrowhead symbol
within an equilateral triangle is intended to alert
the user of the presence of uninsulated
"dangerous voltage" within the product's
enclosure that may be of sufficient magnitude
to constitute a risk of electric shock to persons.
The exclamation point within an equilateral
triangle is intended to alert the user of the
presence of important operating and mainte-
nance (servicing) instructions in the literature
accompanyingthe562E(i.e. this manual).
Caution To prevent electric shock, do not
use the polarized plug supplied
with the 562E with any extension
cord, receptacle, or other outlet
unless the blades can be fully
inserted.
Terms
Several notational conventions are used in this
manual. Some paragraphs may use Note,
Caution, or Warning as a heading. Certain
typefaces and capitalization are used to
identify certain words. These are:
Note Identifies information that needs
extra emphasis. A Note generally
supplies extra information to help
you to better use the 562E.
Equipment Markings
Operator Safety Summary Chapter 2
Caution Identifies information that, if not
heeded, may cause damage to the
562E or other equipment in your
system.
Warning Identifiesinformationthat,if
ignored,maybehazardousto
yourhealthorthatofothers.
CAPITALS Controls, switches or other
markings on the 562E's chassis.
Boldface Strong emphasis.
Power source - This product is intended to
operate from a power source that does not
apply more than 255Vrms between the power
supply conductors or between either power
supply conductor and ground. A protective
ground connection, by way of the grounding
conductor in the power cord, is essential for
safe operation.
Dangerfrom lossof ground- If the protective
ground connection is lost, all accessible
conductive parts, including knobs and controls
that may appear to be insulated, can render an
electric shock.
Properpowercord - Use only thepowercord
specified for the product. Use only a power
cord that is in good condition.
Operating location - Do not operate this
equipment under any of the following condi-
tions: explosive atmospheres, in wet locations,
in inclement weather, improper or unknown AC
mains voltage, or if improperly fused.
Stayoutof the box-To avoid personal injuryor
injury to others, do not remove the product
covers or panels. Do not operate the product
without the covers and panels properly
installed.
AVIS:
NE PAS OUVRIR
Il ne se trouve a l’interieur aucune piece pourvant entre reparée l’usager.
SEE OWNERS MANUAL. VOIR CAHIER D’INSTRUCTIONS.
S’adresser a un reparateur compétent.
RISQUE DE CHOC ELECTRIQUE
N
o user serviceable parts inside. Refer servicing to qualified service personnel
.
CAUTION
WARNING:
TO REDUCE THE RISK OF FIRE OR
ELECTRIC SHOCK DO NOT EXPOSE
THIS EQUIPMENT TO RAIN OR MOISTURE
DO NOT OPEN
RISK OF ELECTRIC SHOCK

562E
3
Fast First-Time Setup
Follow these instructions to get your 562E up-and-running as quickly as possible. The intent of
this section is fast setup. If you need something clarified, then you’ll find the answer elsewhere in
this manual.
Connect the line-level signal source to either the female XLR connector or the 1/4-in.
TRS (tip-ring-sleeve, stereo, 3-conductor) input jack. If the source is unbalanced, then
use a 1/4-in. TS (tip-sleeve, mono, or guitar) plug fully inserted into the TRS input jack.
Connect the line-level signal return to either the male XLR connector or to the 1/4-in.
TRS output jack. If you use the 1/4-in. jack, then use a TRS plug for balanced circuits
or use a TS plug for unbalanced circuits. Additional information on the signal connec-
tions may be found on pages 12-13 of this manual.
Repeat for the second channel. Ignore the SIDECHAIN (KEY INPUT) connections for now.
Connect the AC input to an AC power source of the proper voltage and frequency, as
marked on the rear of the unit.
Caution:Failure to connect the 562E to the proper AC mains voltage may
cause fire and/or internal damage.
Warning: Lethalvoltages are presentinside thechassis. There areno user
serviceablepartsinside thechassis.Referallservicetoqualified
servicepersonnelortothefactory.
Make your initial switch and control settings as follows:
SWITCH SETTING
EXT.KEY/BYPASS/IN IN
KEY LISTEN//W/FILTER//GATE/EXP.GATE/EXP.
LOW CUT (CCW) 10Hz
HIGH CUT (CW) 40K
WINDOW ADVANCE MAX
THRESHOLD -10
ATTACK TIME AUTO
HOLD TIME (GATE ONLY) 50ms
RELEASE TIME 300ms
GATE RANGE (IF GATING) 80dB
EXPANDER RATIO (IF EXPANDING) 1:3
With the 562E’s controls and switches now set according to the preceding section, the 562E
should pass signal. Fast setup is complete.
Refining Your Settings
Refine the THRESHOLD setting so that the expander/gate reduces the gain when the input signal
falls below the threshold setting. Adjust the ATTACK TIME, HOLD TIME and RELEASE TIME controls to
suit the audio that is being fed to the 562E. Percussive sounds usually call for fast attack, hold and
release times; speech and music generally work best with slower times. You can make the expander/
gate stay open for momentary lapses in signal by increasing the setting of the RELEASE and/or
HOLD TIME control. This also affects the rate-of-release once the signal falls below threshold. If
you feel that the expander/gate is dropping the signal too much, try a lower GATE RATIO/EXPANDER
RANGE setting. Remember these settings are just guidelines; you can use whatever settings work
best for you.









Fast Setup
Chapter 3





562E
4
Sidechain Processing Section
EXT.KEY/BYPASS/INswitch-
The EXT. KEY switch position
activates the KEY INPUT on the
rear of the 562E, and allows
externally-triggeredgating/
expansion. The EXT. KEY
switch position must be chosen
in order to use an external
signal, applied to the KEY
INPUT, to control the gating and
expanding action, or to route
the external key signal to the
output of the 562E. The BYPASS switch position disengages the expander and gate functions.
The INswitch position engages the expander and gate functions, using the 562E’s internal
sidechain signal to control the gating and expanding action. The INswitch position also
allows you to route the internal sidechain signal to the output of the 562E. The INswitch
positionisthe normaloperatingswitchsettingforthe562E.
Note If you set the EXT.KEY /BYPASS/INswitch to the EXT.KEY position, with no audio
applied to the KEY INPUT jack on the rear of the 562E, the 562E’s gate/expander will
release (close).
OUTPUT ASSIGN switch - The KEY LISTEN switch position allows you to route the external key
audio or the internal sidechain audio to the output of the 562E. This is useful for monitoring
an external signal that you are applying to the KEY INPUT or for monitoring the internal
sidechain signal. It is also helpful in fine tuning any EQ changes that you are making to the
external signal before it reaches the KEY INPUT of the 562E. The W/FILTER switch position
allows you to monitor the external key audio or the internal sidechain audio at the output of
the 562E, after it has been processed by the LOW CUT and HIGH CUT filters. This is helpful in
fine tuning the effect of the LOW CUT and HIGH CUT filters on the key/sidechain audio. The
GATE/EXP. switch position routes the gated/expanded audio to the output of the 562E. The
GATE/EXP.switchpositionisthenormaloperatingpositionforthe562E.
LOW CUT control - Adjusts the cutoff frequency (3dB-down point) of a high-pass filter that is
applied to the sidechain audio. Sidechain audio at frequencies above the cutoff frequency is
uniformly passed. Use the LOW CUT control to rolloff any rumble and other low frequency
information that you do not want the 562E to use for control.
HIGH CUT control - Adjusts the cutoff frequency (3dB-down point) of a low-pass filter that is
applied to the sidechain audio. Sidechain audio at frequencies below the cutoff frequency is
uniformly passed. Use the HIGH CUT control to rolloff high frequencies that you do not want
the 562E to use for control (example: use it to filter out the hi-hat cymbals when you are using
the 562E to gate the toms on a drum set).
WINDOW ADVANCE switch - Subtly delays the audio signal energy that is fed to the expander/
gate, relative to the audio signal in the sidechain. It permits the expander/gate to open before
the audio signal passes through the VCA, thereby preventing the expander/gate from clipping
the leading edge of the audio signal waveform. Use the MAX switch setting for more delay
(good for drums), and use the MIN switch setting for less delay (great on cymbals). The OFF
position bypasses the WINDOW ADVANCE feature.
Front Panel Overview Chapter 4
HIGH CUT
WINDOW
MAX
20K
4K
ADVANCE
OFF
40K
400Hz MIN
LOW CUT
OUTPUT
200Hz15Hz
ASSIGN
20Hz 50Hz
EXT.KEY KEY LISTEN
1K10Hz
IN GATE/EXP.
BYPASS W/FILTER
CH1 SIDECHAIN PROCESSING
1K

562E
5
(dB)
THRESHOLD
ABOVE
BELOW
0
T
I0N
d
B)
-40 +20
A
CHANNEL 1
TIME E
X
500ms
HOLD
TIME
ATTACK
TIME
60ms 1 Sec
RELEASE
2.5 Sec4 Sec300ms 50ms 30msAUTO
GATE RANGE
EXPANDER RATIO
0
E
1:3
S
ec 80dB
(dB)
THRESHOLD
ABOVE
BELOW
-10
30
X
12
3
REDUCTI0N
GAIN (dB)
-40 +20
60
F
GAIN REDUCTION LED display- The GAIN REDUCTION display
indicates how much the expander/gate has reduced the level
of the input signal.
ABOVE/BELOW LEDdisplay- The ABOVE LED indicates that
the input signal is above threshold. The BELOW LED indicates
that the input signal is below threshold.
GATE RANGE/EXPANDER RATIO control - This control determines the
amount of attenuation that occurs during gating or expansion of the input
signal. For gating, use the settings from 0 (twelve o’clock) to 80dB
(counterclockwise). These settings define the number of dB below unity
gain that the gated signal will be dropped, when gating occurs. For
expansion, use the settings from 0 (actually 1:1, at twelve o’clock) to 1:3
(clockwise). These settings define how much the output level will change
in relation to changes in the input level. For example, at the 1:3 setting, a
5 dB drop below threshold in the input signal would result in a 15dB drop
in the output signal. When this control is set to twelve o’clock, you will
not have any expander or gate action, because the twelve o’clock position
corresponds to 0dB change for gating, and to a 1:1 ratio (change in input equals change in
output) for expansion.
ATTACK TIME control - Determines the speed at which the
expander/gate reaches zero attenuation when the input
signal rises above threshold. The “AUTO” ATTACK TIME
setting is meant to be used in conjunction with the 562E’s
WINDOW ADVANCE feature, to give you an effective attack
timeofzero.
HOLD TIME control - Determines the amountof time
that the gate continues to stay open (the amount of
time that the gate continues to pass signal at zero
attenuation) after the input signal has fallen below
threshold. When the audio source is speech, use long
HOLD TIME settings to prevent the gate from closing during short pauses between words.
RELEASE TIME control - Determines the speed at which the expander/gate closes (i.e. returns to
full attenuation) when the input signal falls below threshold, at the end of the HOLD TIME.
The Expander/Gate Controls
THRESHOLD control - Sets the signal level below which the expander/
gate begins to operate. When the input signal falls below the level
indicated by the THRESHOLD control, the expander/gate begins reducing
the gain. The GAIN REDUCTION LED display indicates how much the
expander/gate has reduced the gain.

562E
6
Rear Panel Overview Chapter 5
Power Cord - IEC power receptacle. Connect the power cord to an appropriate source of AC
power. Observe the marked power supply voltage on rear panel.
BALANCED/UNBALANCED INPUT - 1/4-inch TRS phone
jack. This connector is wired in parallel with the XLR
input connector. Connect either balanced or unbalanced
sources here. Use a tip-sleeve plug for unbalanced
sources and a tip-ring-sleeve (stereo) plug for balanced
sources.
BALANCED INPUT - XLR-3 female connector. This
connector is wired in parallel with the TRS input
connector. Use this connector when you need a
balanced XLR input.
KEY INPUT - 1/4-inch tip-ring-sleeve connector, wired tip=return, ring=send and
sleeve=ground. To trigger the expander/gate from an external audio source,
use the tip of this connector to connect the audio signal that you wish to use
as a key signal to trigger the expander/gate. To externally process the
sidechain signal, use the ring of this connector to feed the sidechain signal to
an external processing device, and use the tip as the return from the external
processing device. The wiring diagram for the KEY INPUT connector is repro-
duced on the back panel of the 562E.
Note: Remember to set the front panel EXT. KEY/BYPASS/INswitch to the EXT.
KEY position when using the KEY INPUT.
BALANCED/UNBALANCED OUTPUT - 1/4-inch tip-ring-sleeve
(TRS)phonejack,wired tip= high(+), ring =low(-) and
sleeve=ground. Use this jack when you need a 1/4-inch
balanced or unbalanced output. The nominal signal level
here is +4 dBu. The wiring diagram for the BALANCED/
UNBALANCED OUTPUt connector is reproduced on the back
panel of the 562E. Note: connecting an unbalanced cable
here will result in an output level that is 6dB lower than the
output level you get if you use a balanced cable.
BALANCED OUTPUT -XLR-3maleconnector,wiredPin
1=ground, Pin 2=high(+) and Pin3=low(-). Use this connector when you need a balanced XLR
output. The nominal signal level here is +4 dBu. The wiring diagram for the BALANCED OUTPUT
connector is reproduced on the back panel of the 562E.
E562 WINDOWING EXPANDER/GATE
MANUFACTURED IN LYNNWOOD, WASHINGTON USA
U
AC INPUT
18 WATTS
MAXIMUM
FABRIQUÉ AUX E.-U. PAR SYMETRIX INC., LYNNWOOD, WA USA.
RÉFÉREZ TOUTE RÉPARATION À UN TECHNICIEN QUALIFIÉ.
CHANNEL 1 OUTPUT
BALANCED
BALANCED/
UNBALANCED
KEY
INPUT
SIDECHAIN
CHANNEL 1 INPUT
UNBALANCED
BALANCED/
BALANCED

562E
7
The Controls in Detail
Threshold
The THRESHOLD control of the 562E sets the audio
signal level at which the expander/gate begins
working. The expander/gate begins working once
the signal has fallen below the threshold level.
The THRESHOLD control setting also determines
the degree or amount of gain reduction (in
conjunction with the GATE RANGE/EXPANDER RATIO
control). An expander/gate with a high threshold
setting will expand or gate the signal much more
than an expander/gate with a low threshold
setting. Clockwise rotation of the THRESHOLD
control (i.e. setting a higher threshold level)
raises the level that the signal must exceed to
trigger the expander/gate to open, so that the
signal can pass through untouched.
The expander/gate has the effect of “shutting off” the signal once it falls to, and then drops
below, the threshold level. The amount that the signal is “shut off” is determined by the GATE
RANGE or EXPANDER RATIO control setting.
Expander Ratio
The 562E uses a downward expander, which only acts on signals that are below threshold.
The EXPANDER RATIO of the 562E dictates how much the output changes for a below-threshold
change in the input. A linear amplifier (like a simple preamp) has a ratio of 1:1 because a
change of 1 dB at its input results in a 1 dB change at its output.
A downward expander magnifies output changes for a below-threshold input change. Thus,
once the input signal falls below threshold, the expander changes the output by the amount
dictated by the ratio. The 562E’s downward expander allows the user to vary the ratio of the
expander from 1:1 to 1:3. When the EXPANDER RATIO control is set to 1:3, a below-threshold
input signal that gets 5 dB quieter causes a 15 dB decrease at the output. In other words, a
small drop in the input signal level (5 dB), occurring below threshold, turns into a much larger
drop in signal level at the output (15dB).
A special feature of the 562E’s ratio circuitry is that the ratio automatically reverts to 1:1 when
the input signal approaches 25dB below threshold. For example, let’s say that you set the
THRESHOLDcontrol to “0dB”, andthe EXPANDER RATIOcontrol for a 1:3ratio. Once the
input signal falls below 0dB, for every 1dB that the input signal drops, the output will drop by
3dB. As the input signal approaches -25dB, the output signal will approach -75dB. However
when the input signal reaches -25dB, the ratio will revert to 1:1 from that point on. This means
that, with the EXPANDER RATIO set to 1:3, when the input drops to -26dB, the output will drop to
-76dB. When the input decreases to -27dB, the output will decrease to -77dB, and so on. This
is to prevent any low level modulation of the expanded signal. (Such modulation can be very
annoying.)
GateRange
The range of a gate is the amount that the output level drops when the gate is triggered
“closed” by the input signal dropping below threshold. The gate range of the 562E is adjust-
able from 0 to 80dBu. If you set the GATE RANGE control to 80dBu, and set the THRESHOLD
control to -10dBu, then every time that the input signal to the 562E drops below -10dBu, the
gate of the 562E will drop the signal by 80dBu. Thus an input signal of -12dBu would result in
-92dBu at the output of the gate. Obviously, when the input signal level is so low that
engaging the gate causes it to drop to a level that is lower than the noise floor of the unit, the
output signal level of the 562E will no longer decrease by 80dBu from the input signal level.
Chapter 6
AUDIO INPUT
LEVEL
THRESHOLD LEVEL
GATE CONTROL
VOLTAGE
AUDIO OUT
ATTACK
RANGE
CONTROL
HOLD
RELEASE

562E
8
Attack
The attack control of a gate/expander allows the user to shape the leading edge of the sound
envelope by manipulating the attack time. The ATTACK TIME control setting can make the transfer
between silence and sound graceful, or it can make the transfer abrupt.
The attack time represents the amount of time that an expander or a gate needs to react to an
input signal rising above threshold. Generally, gating is associated with short attack times
and expansion is associated with longer attack times. For expander applications, such as
removing background noise from speech, you do not want to make the attack time lightning
fast because it can make the audio sound “chopped up”. A slower ATTACK TIME setting is
preferable, so that the expander makes a more graceful transition between silence and speech,
retaining a more natural character to the audio.
For gating applications, such as isolating drum kit microphones, a faster attack time is desired,
so that the gate can open quickly when the input signal rises above threshold (when the drum
is struck). Since much of the audio signal in this case occurs at the moment of impact, a gate
that opens slowly would miss most of the audio signal.
Note The fastest attack time setting on the 562E is the “AUTO” position, which is meant to be
used in conjunction with the WINDOW ADVANCE Feature. The 562E’s WINDOW ADVANCE
feature is designed to open the gate before the audio signal passes through the VCA.
Engaging the WINDOW ADVANCE feature and setting the ATTACK TIME control to “AUTO”
will ensure that the gate will not miss any of the impact portion of the audio signal
generated when the drum is struck.
Release
The release control of a gate/expander allows the user to shape the trailing edge of the sound
envelope by manipulating the release time. The RELEASE TIME control setting can make the
transfer between sound and silence graceful, or it can make the transfer abrupt.
Release time is the length of time required for the gain to recover to the no-signal state. When
you are using the 562E in GATE mode, release time is the length of time required for the gate to
close, because the no-signal state for an audio gate is the closed state. When an above-
threshold signal disappears, the RELEASE TIME control governs how long it takes for the
expander or gate to reduce the gain to the no-signal state.
The RELEASE TIME control permits tailoring of the expander’s or gate’s recovery time to the
program material. Generally, gating is associated with short release times and expansion is
associated with longer release times.
For gating applications, such as isolating drum kit microphones, a faster release time is
desired, so that you can achieve better isolation and less leakage into the microphone from the
other drums in the drum kit. In the case of drums, a “choppy” sound can also be used as a
desired effect (like the infamous gated reverb, commonly used on a snare drum).
Hold
The HOLD TIME control sets the amount of time that the gate passes audio before it begins to
release. A long hold time will give a more natural sound. For example, when the program
material is speech, a long hold time can be used to prevent the gate from releasing (closing)
between words. A short hold time gives tighter control over the audio.
Note: The HOLD TIME only functions in the gate mode.
Hint: If you hear “jitter” (the gate rapidly toggling between the open and closed state), it means that
you have set the HOLD TIME too short, and you need to use a longer hold time setting (unless,
of course, you want that sound).

562E
9
Using the Sidechain Key Input
The sidechain KEY INPUT 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 KEY INPUT, 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 KEY INPUT 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 EXT. KEY/BYPASS/INswitch to the EXT. KEY position.
Then, connect your key signal source to the KEY INPUT jack of the 562E. Now you can adjust the
THRESHOLD and GATE RANGE/EXPANDER RATIO controls for the amount of gating/expansion that you
want. You can then fine-tune your sound, using the ATTACK, HOLD and RELEASE TIME controls, as
well as the WINDOW ADVANCE feature. A typical application for using the KEY INPUT 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 LOW CUT and
HIGH CUT 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 ABOVE and BELOW 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 BELOW
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 ABOVE LED is lit, the signal is above threshold,
and gain reduction is not occurring.
The 562E also has one GAIN REDUCTION LED display per channel. The GAIN REDUCTION 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
GAIN REDUCTION 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 LOW CUT and HIGH CUT sidechain filter controls.

562E
10
The 562E’s internal sidechain signal can also be equalized in this manner. To insert an equalizer in the
sidechain, set the EXT.KEY/BYPASS/INswitch to the EXT. KEY position. Connect an insert cable from the
KEY INPUT of the 562E to the input and output of your equalizer as illustrated in the drawing below.
The562E’sKEY INPUT jackiswired: TIP=RETURN,RING=SEND,andSLEEVE=GROUND.
If the expander/gate is being triggered by an unwanted high frequency signal (such as a squeaky
kick drum pedal), you can prevent the expander/gate from responding to that portion of the key
signal by cutting high frequencies and/or boosting low frequencies in the key signal. This can be
accomplished by careful adjustment of the corresponding threshold control, combined with the
boost/cut provided by the HIGH CUT filter and/or the EQ in the sidechain.
Note Seealso“PreventingFalseTriggeringbyHi-hatandKick While Gating a Snare Drum” on page15.
If low frequency signals transmitted through a desk or podium are triggering the 562E’s expander
unnecessarily, use the LOW CUT filter to remove the low frequencies from the control signal, or use
an equalizer in the sidechain to boost the voice-range frequencies in the control signal.
Hint: You can save time, and make your life easier, by listening to the equalized external key
signal or to the equalized internal sidechain signal (instead of the 562E’s GATE/EXP.
output). When using an external equalizer, listen to the equalized key/sidechain signal by
setting the EXT.KEY/BYPASS/INswitch to the EXT.KEY position, and the OUTPUT ASSIGN
switch to the KEY LISTEN W/FILTER position. If you are not using an external equalizer, and
you want to hear the effect of the LOW CUT and HIGH CUT filters on the internal sidechain
audio, set the EXT.KEY/BYPASS/INswitch to the INposition, and the OUTPUT ASSIGN switch
to the KEY LISTEN W/FILTER position. Listening to the EQ’d key/sidechain signal allows you
to hear the signal that will control the 562E, and to more easily find the range that you wish
to emphasize or de-emphasize. When you are done listening to the EQ’d key/sidechain
signal, return the OUTPUT ASSIGN switch to the GATE/EXP. position for normal operation.
Keep in mind that the threshold level becomes a function of the amount of overall gain through the equalizer,
including the boost. If you increase the overall gain in the sidechain signal, by boosting selected frequencies
with the equalizer, you will need to also raise the THRESHOLD setting, in order to maintain the same signal level:
threshold level relationship that you had before boosting the frequencies.
Note There is no substitute for good mic technique. The more that you isolate the desired
signal from any undesired signal, using the rear-axis rejection characteristics of a
directional mic to your advantage, the easier it will be for you to achieve optimum gating
performance. Forexample, when miking a snare drum that is to be gated, it is generally a
good idea to mic the snare drum with the rear of the mic towards the hi-hat cymbal, to
reduce the amount of hi-hat leakage into the snare mic, thus reducing the possibility of the
gate being falsely triggered by the hi-hat. The sound picked up by each mic should be
primarily the sound of the desired signal.
CHANN
E
UNBALANCED
BALANCED/
KEY
INPUT
BALANCED/
BALANCED
OUTPUTS
UNBALANCED
CHANNEL 1 OUTPUT
BALANCED
TYPICAL CONNECTIONS
13
SIDECHAIN
1
3
2
LOW(-)=PIN 3
HIGH(+)=PIN 2
GROUND=PIN 1
1/4"BALANCED
BALANCED
INPUTS
TIP=HIGH(+)
RING=LOW(-)
BALANCED
SLEEVE=GROUND GROUND
SIDECHAIN OUT
KEY INPUT
2
SIDECHAIN
A
LANCED
L
ANCED/
CHANNEL 2 INPUT
EQ
Send
Return
Ground
Return
(from EQ output)
Send
(to EQ input)

562E
11
Connecting to Other GearChapter 7
Matching Levels vs Matching Impedances
In any audio equipment application, the question of “matching” inevitably comes up. Without
digging a hole any deeper than absolutely necessary, we offer the following discussion to (hope-
fully) clarify your understanding of the subject.
Over the years, we have all had impedance matching pounded into our heads. This is important
only for ancient audio systems, power amplifiers, and RF. Technically speaking, the reason is
power transfer, which reaches a maximum when source and load are matched. Modern audio
systems are voltage transmission systems and source and load matching is not only unnecessary,
but undesirable as well.
rAncient audio systems operate at 600 ohms (or some other impedance value), and must be
matched, both at their inputs and at their outputs. Generally speaking, if you are dealing
with equipment that uses vacuum tubes, or was designed prior to 1970, you should be
concerned about matching. These units were designed when audio systems were based on
maximum power transfer, hence the need for input/output matching.
rPower amplifiers are fussy because an abnormally low load impedance generally means a
visit to the amp hospital. Thus, it’s important to know what the total impedance of the pile
of speakers connected to the amplifier really is.
rRF systems are matched because we really are concerned with maximum power transfer
and with matching the impedance of the transmission line (keeps nasty things from
happening). Video signals (composite, baseband, or otherwise) should be treated like RF.
Some folks seem to believe that balanced/unbalanced lines and impedances are related; or even
worse that they are associated with a particular type of connector. Not so. Unbalanced signals are
not necessarily high-impedance and balanced signals/lines are not necessarily low-impedance.
Similarly, although 1/4 inch jacks are typically used for things like guitars (which are high-imped-
ance and unbalanced), this does not predispose them to only this usage. After all, 1/4 inch jacks
are sometimes used for loudspeakers, which are anything but high-impedance. Therefore, the
presence of 3-pin XLR connectors should not be construed to mean that the input or output is low-
impedance (or high-impedance). The same applies to 1/4 inch jacks.
So, what is really important? Signal level, and (to a much lesser degree), the impedance relation
between an output (signal source) and the input that it connects to (signal receiver).
Signal level is very important. Mismatch causes either loss of headroom or loss of signal-to-noise ratio.
Thus, microphone inputs should only see signals originating from a microphone, a direct (DI) box, or an
output designated microphone-level output. Electrically, this is in the range of approximately -70 to -20
dBm. Line inputs should only see signals in the -10 to +24 dBm/dBu range. Guitars, high-impedance
microphones, and many electronic keyboards do not qualify as line-level sources.
The impedance relation between outputs and inputs needs to be considered, but only in the
following way - Always make sure that a device’s input impedance is higher than the output
source impedance of the device that drives it.
Some manufacturers state a relatively high-impedance figure as the output impedance of their
equipment. What they really mean is that this is the minimum load impedance that they would like
their gear to see. In most cases, seeing a output impedance figure of 10,000 (10K) ohms or higher
from modern equipment that requires power (batteries or AC) is an instance of this type of rating. If
so, then the input impedance of the succeeding input must be equal to or greater than the output
impedance of the driving device.
Symetrix equipment inputs are designed to bridge the output of whatever device drives the input
(i.e. to be greater than 10 times the actual source impedance). Symetrix equipment outputs are
designed to drive 600-ohm or higher loads (600-ohm loads are an archaic practice that won’t go
away). You don’t need to terminate the output with a 600-ohm resistor if you aren’t driving a 600-
ohm load. (If you don’t understand the concept of termination, you probably don’t need to
anyway.)

562E
12
The two facts that you need to derive from this discussion are:
rMatch signal levels for best headroom and signal-to-noise ratio.
rFor audio, impedance matching is only needed for vintage equipment and power amplifier
outputs. In all other cases, ensure that your inputs bridge your outputs (meaning the
inputs are in the range of 2 to 200 times the output source impedance) .
Signal Levels
The 562E is designed around studio/professional line levels: +4 dBu or 1.23 volts RMS. The unit is
quiet enough to operate at lower signal levels such as those found in semipro or
musical-instrument(MI)equipment(-10dBuor300millivolts).
I/O Impedances
The 562E is designed to interface into almost any recording studio or sound reinforcement applica-
tion. This includes:
r600-ohm systems where input and output impedances are matched.
rUnbalanced semiprofessional equipment applications.
rModern bridging systems where inputs bridge and outputs are low source impedances
(voltage transmission systems).
The 562E’s input impedance is greater than 20-kilohms balanced or 10K unbalanced. The inputs
may be driven from any source (balanced or unbalanced) capable of delivering at least -10 dBu into
the aforementioned impedances.
The 562E’s output impedance is 600 ohms balanced, 300 ohms unbalanced. The output line driver
delivers+22 dBm into600-ohm balanced loadsor +18 dBminto 600-ohm unbalancedloads.
Polarity Convention
The 562E inputs and outputs use the international standard polarity convention of pin 2 hot.
Therefore, if your system uses balanced inputs and outputs, and uses the 562E this way, then the
polarity convention is unimportant. If your system is both balanced and unbalanced, then you
must pay attention to this, especially when going in and coming out through different connector
types (like input on an XLR, output on a phone jack).
XLR 1/4" Phone Signal
Pin1 Sleeve Ground
Pin2 Tip High
Pin3 Ring Low
Input and Output Connections
The illustration on the next page shows how to connect the 562E to balanced and unbalanced
sources and loads.
To operate the 562E from unbalanced sources, run a 2-conductor shielded cable (that’s two
conductors plus the shield) from the source to the 562E. At the source, connect the low/minus side
to the shield, these connect to the source’s ground; connect the high/plus side to the source’s
signal connection. At the 562E, the high/plus wire connects to pin 2, the low/minus wire connects
to pin 3, and the shield (always) connects to pin 1. This is the preferred method as it makes best
use of the 562E’s balanced input (even though the source is unbalanced). The other alternative
shown in the illustration converts the 562E’s balanced input into an unbalanced input at the input
connector. This works, but is more susceptible to hum and buzz than the preferred method. There
is no level difference between either method.

562E
13
You can drive unbalanced loads with the 562E’s outputs by using the XLR connector with pin 3
left open. In an emergency (the show must go on), you can ground pin 3, but if you have the
choice...leave it open. If you must ground pin 3, it is must be grounded at the 562E, rather than at
the other end of the cable. The price, regardless of whether or not pin 3 is grounded is 6 dB less
output level. If your system is wired with pin 3 hot, and you are driving an unbalanced load, pin 2
mustfloat.
The 1/4-inch input jack is paralleled with the XLR-input. In a large installation, it is permissible to
use one of the connectors as the input connection and to use either or both of the remaining
connections for paralleling other inputs with the 562E.
The 1/4-inch output jack is a TRS (tip-ring-sleeve) jack wired for balanced operations. This jack may
also be used for unbalanced operation. The unbalanced output is always 6 dB lower in level than the
balanced output.
FROM BALANCED OUT
(TO UNBALANCED IN)
FROM ELECTRONIC, NON-TRANSFORMER
BALANCED OUTPUT (TYPICAL OF SYMETRIX PRODUCTS)
TO UNBALANCED INPUTS
FROM BALANCED OUT
FROM UNBALANCED OUT
FROM BALANCED OUT
FROM BALANCED OUT
FEMALE XLR
PIN 1 = GROUND
PIN 2 = HIGH
PIN 3 = LOW
MALE XLR
PIN 1 = GROUND
PIN 2 = HIGH
PIN 3 = LOW
MALE TS PLUG
TIP = HIGH
SLEEVE = GROUND +
LOW
MALE RCA PLUG
TIP = HIGH
SLEEVE = GROUND +
LOW
MALE TRS PLUG
TIP = HIGH
RING = LOW
SLEEVE = GROUND
MALE TRS PLUG
TIP = HIGH
RING = LOW
SLEEVE = GROUND
MALE TRS PLUG
TIP = HIGH
RING = NOT USED
SLEEVE = GROUND+
LOW
MALE TS PLUG
TIP = HIGH
SLEEVE = GROUND +
LOW
MALE RCA PLUG
TIP = HIGH
SLEEVE = GROUND +
LOW
MALE TS PLUG
TIP = HIGH
SLEEVE = GROUND +
LOW
MALE RCA PLUG
TIP = HIGH
SLEEVE = GROUND +
LOW
TERMINAL STRIP
(+) = HIGH
(-) = LOW
= GROUND
TERMINAL STRIP
(+) = HIGH
(-) = LOW
= GROUND
TERMINAL STRIP
(+) = HIGH
(-) = UNUSED
= GROUND
TERMINAL STRIP
(+) = HIGH
(-) = NOT USED
= GROUND
FEMALE XLR
PIN 1 = GROUND + LOW
PIN 2 = HIGH
PIN 3 = NOT USED
2
2
2
3
3
3
1
1
1
RINGRING
RING
SLEEVESLEEVE
S
LEEVE
TO BALANCED IN
TO BALANCED IN
TO BALANCED IN
(FROM UNBALANCED OUT)
TO UNBALANCED IN
TIPTIP
TIP
TO UNBALANCED IN FROM
TRANSFORMER COUPLED OR
FLOATING BALANCED OUTPUT
TO BALANCED IN

562E
14
The 562E Auto Windowing Expander Gate can provide signal processing capabilities ranging from
essential to esoteric. Some of the following techniques are standard and straightforward. Other
techniques may be used less commonly, but are worthy of investigation. These examples are
intended to give you some sample setups that you can use right away, but they are not intended to
represent every possible use of the Symetrix 562E.
Perhaps the most common use for gates in music production is on drum and percussion tracks. In
addition, gates may be used on virtually any type of musical instrument or audio sound effect to
remove unwanted room noise and ambience, to modify reverb and other time-related effects, and to
create special effects.
The downward expander is ideal for tasks requiring more subtle control. Expanders can provide
single-ended noise reduction for tape recorders, workstations, effects devices, companding (when
used with a compressor), and noise and interference suppression for studio and live sound.
Noise Elimination
The 562E is capable of eliminating noise on a track or channel that becomes objectionable when
not masked by the desired signal. For general and gentle noise suppression (especially on voice),
use expansion. For more “hardline” noise suppression, use gating.
You can use the 562E to reduce body noises picked up by an announce microphone, to reduce amp
noise from a noisy guitar amp, or to reduce the amount of room sound in a guitar track that was
recorded a little too loosely in a room that was a little too noisy. For sound reinforcement, the 562E
is useful for tending an announce mic that needs to be left on, when you really don’t want it
picking up every whisper in its vicinity or going into feedback.
Setup for these applications is easy. With no signal and the GATE RANGE/EXPANDER RATIO control
either clockwise (for expanding) or counterclockwise (for gating), adjust the THRESHOLD control
counterclockwise until you begin to see gain reduction on the LED display. Continue until you
hear the degree of expansion/gating that you want. When the signal is present, you may need to
refine the setting so that the 562E doesn’t reduce the gain during momentary pauses. You can slow
things down a bit via the HOLD and RELEASE controls, which help prevent expansion/gating during
momentary pauses. Remember: The HOLD control only functions while gating.
Isolating and Tightening Up Drum Sounds
The damping effect achieved by applying duct tape to a drum head is very similar to the effect of
applying gating or expanding to the drums. The duct tape reduces the decay (sustain) of the
instrument, and helps get rid of annoying ring frequencies. Using the 562E to reduce the decay of
individual drums allows the drummer to play with the full power of his or her drums, at live perfor-
Applications Chapter 8
CHANNEL 1
TIME GATE RANGE EXPANDER RATIO
500ms 0
HOLD
TIME
ATTACK
TIME
60ms 1 Sec
RELEASE
1:3
2.5 Sec 80dB 4 Sec300ms 50ms 30ms
(dB)
THRESHOLD
ABOVE
BELOW
0
HIGH CUT
WINDOW
30
MAX 12
20K
4K
ADVANCE
3
REDUCTI0N
GAIN (dB)
-40 +20
60
OFF
40K
400Hz MIN AUTO
LOW CUT
OUTPUT
200Hz15Hz
ASSIGN
20Hz 50Hz
EXT.KEY KEY LISTEN
1K10Hz
IN GATE/EXP.
BYPASS W/FILTER
CH1 SIDECHAIN PROCESSING
1K
CHANNEL 1
TIME GATE RANGE EXPANDER RATIO
500ms 0
HOLD
TIME
ATTACK
TIME
60ms 1 Sec
RELEASE
1:3
2.5 Sec 80dB 4 Sec300ms 50ms 30ms
(dB)
THRESHOLD
ABOVE
BELOW
0
HIGH CUT
WINDOW
30
MAX 12
20K
4K
ADVANCE
3
REDUCTI0N
GAIN (dB)
-40 +20
60
OFF
40K
400Hz MIN AUTO
LOW CUT
OUTPUT
200Hz15Hz
ASSIGN
20Hz 50Hz
EXT.KEY KEY LISTEN
1K10Hz
IN GATE/EXP.
BYPASS W/FILTER
CH1 SIDECHAIN PROCESSING
1K

562E
15
mance levels, while providing the engineer with the kind of control that is necessary for a good,
tight track.
In a live sound reinforcement situation, gating drums can tighten up the drum sound. Equally
important, gates allow the sound engineer to turn up the drums louder than would normally be
possible without feedback. This is because a correctly set gate can suppress feedback while the
feedback is at a lower level than the setting of the gate’s threshold (before the feedback has a
chance to take off).
Careful adjustment of the ATTACK and RELEASE controls allow the relative balance between the
drum’s impact and decay to be changed. Short ATTACK, HOLD and RELEASE times emphasize the
impact portion of the sound, but may sound artificial in some situations. Longer ATTACK, HOLD and
RELEASE times generally sound more natural, but allow more ringing and feedback. The WINDOW
ADVANCE feature can be used to ensure that the gate opens in time to catch all of the impact portion
of the sound. The GATE RANGE/EXPANDER RATIO will affect the ATTACK and RELEASE times, so use as
much attenuation as needed, but no more than necessary. Be prepared for some serious fine
tuning of these controls.
Note Be sure to select microphones with good off-axis rejection (including high frequencies)
and use the directional patterns of your microphones to isolate the desired signal as much
as possible at the source. The sounds picked up by the microphones must be primarily the
desired sounds, or the gate won’t be able to discriminate between the desired sound and
an unwanted sound.
Preventing False Triggering by Hi-hat and Kick While Gating a Snare Drum
A common problem that engineers run into when they try to gate a snare drum is false triggering.
This is most often caused by audio leakage into the snare mic from the hi-hat and/or kick drum.
The 562E’s LOW CUT and HIGH CUT filters are designed to eliminate just such a problem.
First, and foremost, employ good mic technique to reject as much of the sound that is causing the
false triggering as possible. Start with the 562E’s LOW CUT knob in the full counterclockwise
position, the HIGH CUT knob in the full clockwise position, the THRESHOLD knob in the counter-
clockwise position and the GATE RANGE knob in the full counterclockwise position. While the
drummer plays just the snare and hi-hat, adjust the THRESHOLD control clockwise until gating
occurs (even though the hi-hat may trigger the gate at this point).
Next, set the OUTPUT ASSIGN switch to the KEY LISTEN W/FILTER (center) position. Rotate the HIGH
CUT control to its full counterclockwise position. The hi-hat should now be much less audible, and
the snare should be a muffled “thud”.
Set the OUTPUT ASSIGN switch to the GATE/EXP. position. You may need to readjust the THRESHOLD
control slightly to make the gate trigger properly. The snare should now be gated without any
CHANNEL 1
TIME GATE RANGE EXPANDER RATIO
500ms 0
HOLD
TIME
ATTACK
TIME
60ms 1 Sec
RELEASE
1:3
2.5 Sec 80dB 4 Sec300ms 50ms 30ms
(dB)
THRESHOLD
ABOVE
BELOW
0
HIGH CUT
WINDOW
30
MAX 12
20K
4K
ADVANCE
3
REDUCTI0N
GAIN (dB)
-40 +20
60
OFF
40K
400Hz MIN AUTO
LOW CUT
OUTPUT
200Hz15Hz
ASSIGN
20Hz 50Hz
EXT.KEY KEY LISTEN
1K10Hz
IN GATE/EXP.
BYPASS W/FILTER
CH1 SIDECHAIN PROCESSING
1K
CHANNEL 1
TIME GATE RANGE EXPANDER RATIO
500ms 0
HOLD
TIME
ATTACK
TIME
60ms 1 Sec
RELEASE
1:3
2.5 Sec 80dB 4 Sec300ms 50ms 30ms
(dB)
THRESHOLD
ABOVE
BELOW
0
HIGH CUT
WINDOW
30
MAX 12
20K
4K
ADVANCE
3
REDUCTI0N
GAIN (dB)
-40 +20
60
OFF
40K
400Hz MIN AUTO
LOW CUT
OUTPUT
200Hz15Hz
ASSIGN
20Hz 50Hz
EXT.KEY KEY LISTEN
1K10Hz
IN GATE/EXP.
BYPASS W/FILTER
CH1 SIDECHAIN PROCESSING
1K

562E
16
false triggering by the hi-hat.
With the OUTPUT ASSIGN switch still in the GATE/EXP. position, have the drummer play the snare
again, but this time with kick drum accompaniment. If the kick drum is falsely triggering the snare
gate, rotate the LOW CUT control towards the clockwise position until the kick drum no longer
triggers the gate.
GatedReverb
You knew this was coming, didn’t you?
The obvious method to gate reverb is to feed the reverb to the input of the 562E, and to use the
internal triggering. However, if you use a HOLD TIME setting that is too short, you can run into
jitter problems when the reverb signal starts to decay.
To avoid this, and still be able to use a short HOLD TIME setting, feed a separate send of only the
dry signal to the KEY INof the 562E. Set the EXT. KEY/BYPASS/INswitch to the EXT.KEY position.
Feed the reverb to the audio input of the 562E. This will give the gate a trigger with a well-defined
beginning and end.
Be sure to experiment with the WINDOW ADVANCE feature, especially on instrument sounds with a
sharp attack, such as drums.
Set the other controls as shown in the following illustration.
Noise Reduction and Feedback Control In Vocal Monitors
Here is one of the golden uses of the 562E - increasing gain before feedback and cleaning up the
audio in stage monitor systems. This use of the 562E requires some fine tuning of the THRESHOLD,
LOW CUT and HIGH CUT controls, but it can make a huge contribution towards ease of life for the
monitormixingengineer.
First, set up the 562E, using the downward expander, with a fairly fast release time. The threshold
should be set to trigger on normal level speech.
Set the OUTPUT ASSIGN switch to KEY LISTEN W/FILTER. If the stage setup does not include a drum
kit, you can skip the next step.
If the stage setup includes a drum kit, start turning the HIGH CUT control from fully clockwise
toward counterclockwise until you have eliminated as much of the sound of the cymbals as
possible, without detracting from the vocals.
If you wish, apply some rolloff to the lows using the LOW CUT control. This will help prevent the
downward expander from triggering if the singer likes to rock the mic stand.
CHANNEL 1
TIME GATE RANGE EXPANDER RATIO
500ms 0
HOLD
TIME
ATTACK
TIME
60ms 1 Sec
RELEASE
1:3
2.5 Sec 80dB 4 Sec300ms 50ms 30ms
(dB)
THRESHOLD
ABOVE
BELOW
0
HIGH CUT
WINDOW
30
MAX 12
20K
4K
ADVANCE
3
REDUCTI0N
GAIN (dB)
-40 +20
60
OFF
40K
400Hz MIN AUTO
LOW CUT
OUTPUT
200Hz15Hz
ASSIGN
20Hz 50Hz
EXT.KEY KEY LISTEN
1K10Hz
IN GATE/EXP.
BYPASS W/FILTER
CH1 SIDECHAIN PROCESSING
1K
CHANNEL 1
TIME GATE RANGE EXPANDER RATIO
500ms 0
HOLD
TIME
ATTACK
TIME
60ms 1 Sec
RELEASE
1:3
2.5 Sec 80dB 4 Sec300ms 50ms 30ms
(dB)
THRESHOLD
ABOVE
BELOW
0
HIGH CUT
WINDOW
30
MAX 12
20K
4K
ADVANCE
3
REDUCTI0N
GAIN (dB)
-40 +20
60
OFF
40K
400Hz MIN AUTO
LOW CUT
OUTPUT
200Hz15Hz
ASSIGN
20Hz 50Hz
EXT.KEY KEY LISTEN
1K10Hz
IN GATE/EXP.
BYPASS W/FILTER
CH1 SIDECHAIN PROCESSING
1K

562E
17
Return the OUTPUT ASSIGN switch to the GATE/EXP. setting and do your final threshold adjustments
as well as any filter fine tuning.
You may prefer to use the 562E’s gate if the downward expander is not providing enough signal
attenuation for you.
Cleaning Up Backing Vocals
A common problem with recording backing vocals, especially when layering multiple tracks of
them, is that the beginnings and endings of lines or phrases can get sloppy. All it takes is for a
singer to be a fraction of a second early in starting or late in stopping. The following technique,
using the 562E, won’t help with timing differences during the line or phrase, but it will help greatly
in tightening up backing vocals with uneven starts and stops. This can make a valuable contribu-
tion to your mix, as the beginnings and endings of lines and phrases are the points when timing
problems are most obvious to the listener.
Mix all of the backing vocals into one subgroup (two for stereo), and feed the subgroup output(s)
to the 562E input(s). Select the backing vocal track with the best timing, and send it to an auxiliary
mixer output. Feed this auxiliary output into the KEY INPUT of the 562E. This will be the signal that
you use to trigger the gate.
Set the EXT.KEY/BYPASS/INswitch to EXT.KEY, set the OUTPUT ASSIGN switch to GATE/EXP. and set
the WINDOW ADVANCE switch to MAX. Set the THRESHOLD control counterclockwise, set the ATTACK
TIME and RELEASE TIME controls to a medium setting, set the HOLD TIME counterclockwise, and set
the GATE RANGE control counterclockwise.
Begin rotating the THRESHOLD control clockwise until gating occurs. Then, fine-tune the THRESH-
OLD, ATTACK TIME and RELEASE TIME controls for the best sound.
Midi Control Of The 562E
OK, you can’t directly control the 562E by MIDI. However, there is a clever trick you can use to
control it indirectly, if you have a midi-controlled synthesizer output that you can spare.
Connect the synth output to the KEY INof the 562E, and set the EXT.KEY/BYPASS/INswitch to
EXT.KEY. Now, when the synthesizer plays a sustained note at a constant level, with fast attack
and decay, it will act as a switch to turn the gate off and on. Simply write your midi program so that
the synthesizer is playing a note for the duration of the time that you want the 562E to be passing
signal.
CHANNEL 1
TIME GATE RANGE EXPANDER RATIO
500ms 0
HOLD
TIME
ATTACK
TIME
60ms 1 Sec
RELEASE
1:3
2.5 Sec 80dB 4 Sec300ms 50ms 30ms
(dB)
THRESHOLD
ABOVE
BELOW
0
HIGH CUT
WINDOW
30
MAX 12
20K
4K
ADVANCE
3
REDUCTI0N
GAIN (dB)
-40 +20
60
OFF
40K
400Hz MIN AUTO
LOW CUT
OUTPUT
200Hz15Hz
ASSIGN
20Hz 50Hz
EXT.KEY KEY LISTEN
1K10Hz
IN GATE/EXP.
BYPASS W/FILTER
CH1 SIDECHAIN PROCESSING
1K

562E
18
Noise Reduction for Effects Returns
One of the most overlooked noise sources in sound reinforcement or recording systems is signal
processing. Devices such as reverberation units, digital delays, harmonizers, etc. all have the
potential to enhance the sound, but each device added to the signal chain is going to add a certain
amount of noise, thus diminishing the overall signal-to-noise ratio. The very nature of compres-
sors and limiters raises the apparent noise floor of a signal as the dynamic range is squashed.
The 562E’s downward expander can help you overcome this problem. Try patching the 562E
between the effects sends and the effects returns on the console. Use slower HOLD TIME and
RELEASE TIME settings to preserve the natural decay times of reverbs, etc.
Noise Reduction for Console Outputs
If you have a noise problem at your console outputs, it is best to find the source of the noise
problem, and fix it at the source. However, in a crunch, the 562E can greatly improve the apparent
signal-to-noise ratio of sound reinforcement consoles. One 562E can be used to gate the mono or
stereo output of the board, or multiple 562E’s can be used to gate the subgroup outputs.
When using the 562E on the main output(s) of the console, use gating with a mid to slow release
time, or use downward expansion.
When using the 562E on the subgroup outputs of the console, use gating for the outputs carrying
a fast transient signal (for example: drums or percussion). For subgroup outputs dedicated to
signal sources with gentler dynamics, such as vocals, use slower ATTACK TIME, RELEASE TIME and
HOLD TIME settings when gating, or use downward expansion.
CHANNEL 1
TIME GATE RANGE EXPANDER RATIO
500ms 0
HOLD
TIME
ATTACK
TIME
60ms 1 Sec
RELEASE
1:3
2.5 Sec 80dB 4 Sec300ms 50ms 30ms
(dB)
THRESHOLD
ABOVE
BELOW
0
HIGH CUT
WINDOW
30
MAX 12
20K
4K
ADVANCE
3
REDUCTI0N
GAIN (dB)
-40 +20
60
OFF
40K
400Hz MIN AUTO
LOW CUT
OUTPUT
200Hz15Hz
ASSIGN
20Hz 50Hz
EXT.KEY KEY LISTEN
1K10Hz
IN GATE/EXP.
BYPASS W/FILTER
CH1 SIDECHAIN PROCESSING
1K
CHANNEL 1
TIME GATE RANGE EXPANDER RATIO
500ms 0
HOLD
TIME
ATTACK
TIME
60ms 1 Sec
RELEASE
1:3
2.5 Sec 80dB 4 Sec300ms 50ms 30ms
(dB)
THRESHOLD
ABOVE
BELOW
0
HIGH CUT
WINDOW
30
MAX 12
20K
4K
ADVANCE
3
REDUCTI0N
GAIN (dB)
-40 +20
60
OFF
40K
400Hz MIN AUTO
LOW CUT
OUTPUT
200Hz15Hz
ASSIGN
20Hz 50Hz
EXT.KEY KEY LISTEN
1K10Hz
IN GATE/EXP.
BYPASS W/FILTER
CH1 SIDECHAIN PROCESSING
1K
CHANNEL 1
TIME GATE RANGE EXPANDER RATIO
500ms 0
HOLD
TIME
ATTACK
TIME
60ms 1 Sec
RELEASE
1:3
2.5 Sec 80dB 4 Sec300ms 50ms 30ms
(dB)
THRESHOLD
ABOVE
BELOW
0
HIGH CUT
WINDOW
30
MAX 12
20K
4K
ADVANCE
3
REDUCTI0N
GAIN (dB)
-40 +20
60
OFF
40K
400Hz MIN AUTO
LOW CUT
OUTPUT
200Hz15Hz
ASSIGN
20Hz 50Hz
EXT.KEY KEY LISTEN
1K10Hz
IN GATE/EXP.
BYPASS W/FILTER
CH1 SIDECHAIN PROCESSING
1K