Symetrix 531E User manual

531E and 532E
Graphic Equalizers
Users Guide
531E 532E
/

i
Table of Contents
Chapter 1 Introduction 1
Chapter 2 Operator Safety Summary 2
Chapter 3 Fast Set-Up 3
Chapter 4 Front Panel Controls 4
Chapter 5 Rear Panel Connections 7
Chapter 6 Troubleshooting 8
Chapter 7 Specifications 9
Chapter 8 Warranty and Service 11
Appendix A Flow Chart 13
Appendix B Input/Output Connections 14
Appendix C Declaration of Conformity 15
Rev A.02, 21 July, 1997
Symetrix part number 53531E0A02
Subject to change at our whim and fancy without notice.
©1996, 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 information storage and
retrieval system, without permission, in writing, from
Symetrix, Inc.
Symetrix Inc.
6408 216th St. SW
Mountlake Terrace,WA 98043 USA
Tel [phone]
Fax [phone]
Email [e-mail]
Website www.symetrixaudio.com
531E 532E
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1
531E 532E
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IntroductionChapter 1
Thank you for choosing a Symetrix Graphic
Equalizer. We think you will be glad that you
made this choice because, out of the sea of
graphic eqs that you might have purchased, the
531E and 532E are the only affordable
equalizers that offer truly professional perfor-
mance.
How did we do this? First, because our design
team believes that no one should have to settle
for good enough, they threw out the conven-
tional design ideas and started from scratch.
The result: a highly advanced filter topology
that delivers extremely low distortion and
noise, even at very high signal levels.
Second, our state-of-the-art facility gives us
the ability to build quickly, consistently, and in
high volume, allowing us to keep our prices
low. In addition, the 531E and 532E make
extensive use of surface-mount components.
This allows us to cram more circuitry onto a
smaller circuit board, further reducing costs.
In fact, the 531E and 532E are a purists dream
- audiophile sound quality, uncluttered control
surface, and rugged reliability in one package.
They offer thirty-one filter bands per channel
on ISO 1/3rd octave centers. Through the use
of a global range switch, each band delivers
either 6dB or 12dB of cut or boost. The
grounded center detent position on each band
serves as an on/off switch that completely
removes that band from the audio signal path.
In addition, they sport 12dB per octave High
Cut and Low Cut filters. Each has a sweepable
cutoff frequency and a control range that
extends well into the sub/ultrasonic.
Of course, the controls and features are
secondary to the all important question: How
does it sound? Consider the following facts.
Our proprietary filter technology delivers the
lowest noise floor of any graphic equalizer in
the world, ultra-accurate summing, and
minimal ringing and phase shift. The total
harmonic distortion is less than 0.002%.
Translation: the 531E and 532E are clean,
clear, and musical-sounding.
To ensure the highest level of year-after-year
performance, we build the 531E and 532E to
touring standards. Double sided, glass epoxy
circuit boards, metal shaft, plastic film slide
potentiometers, gold-plated XLR connectors,
and a heavy duty all-steel chassis deliver
rugged reliability. You dont have to treat these
with kid gloves.
The details are worth noting, too. High-contrast
front panel graphics make your control settings
easy to read even in a darkened concert hall.
Servo-balanced outputs remove all DC offset
from the 531E or 532Es output. This elimi-
nates the need for DC blocking capacitors in
the signal path while improving noise, distor-
tion, and low-frequency performance. Of
course, the 531E and 532E incorporate a high-
current, internal power supply with an IEC-
type detachable power cord. No wall warts
here!
We recommend that you read this manual
cover-to-cover. Youll find the answers to most
of your questions inside. However, if you are
in a hurry, go directly to the Fast First-Time
Setup section. It will get you started quickly.
Should you have any comments or questions,
please do not hesitate to contact us at the
numbers/addresses below. Your calls are
always welcome.
Phone [phone]
Fax [phone]
Email [email protected]
EQUALIZER
GRAPHIC
+12
+6
20K16K12.5K10K
0
-6
-12
16K 20K10K 12.5K
8K6.3K5K4K3.15K2K 2.5K1.25K800 1K630500400315 1.6K
6.3K 8K4K 5K3.15K2K 2.5K1.25K800 1K500315 400 630 1.6K
250160 20010063 80 1254025 31.520
+12
+6
50
200160 25010063 80 125
18K
HIGH CUT
±12dB
BYPASS
42K
3K 65K
MODE 0
4025 31.5
-6
-12
20 50
22
LOW CUT
50
U
INPUT
5K
115
6 260
8
∞
- +15
CLIP
E
10dB
0dB
POWER
-20dB
LEVEL
531
CUT FILTERS
+6
+3
-3
-6
+6
+3
±6dB
-3
-6
+12
0
16K10K 12.5K 20K
-12
+12
16K12.5K10K 20K
-12
16K12.5K10K 20K
0
8K5K4K 6.3K3.15K2K 2.5K1.25K800 1K500400315 630 1.6K
4K 8K6.3K5K3.15K2K 2.5K
4K 8K6.3K5K3.15K2K 2.5K
1.25K1K800500400315 630
1.25K1K800500400315 630
1.6K
1.6K
25020016010063 80 1254025 31.520
0
CH1
18K
HIGH CUT
MODE
50
250160 20010063 80 125
25020016010063 80 125
4025 31.5
BYPASS
±12dB
3K 65K
18K
HIGH CUT CH2
20
4025 31.5
±12dB
BYPASS
42K
3K 65K
MODE
20
0
50
50
42K
22 50
LOW CUT
U
INPUT
CLIP
CH1 LEVEL
115
6 260
8
∞
+15
LOW CUT
U
INPUT
0dB
-20dB
E
CH2 LEVEL
115 5K
6 260
8
∞
+15
10dB
-20dB
0dB
POWER
22 50
CLIP
EQUALIZER
GRAPHIC
532
5K
10dB
CH1 CUT FILTERS
CH2 CUT FILTERS
+6
-6
+6
-6
±6dB
±6dB

2
531E 532E
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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; they do not appear
in this summary.
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
accompanying the product (i.e. this manual).
Caution To prevent electric shock, do not
use the polarized plug supplied
with the unit 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 or 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 product.
Equipment Markings
Operator Safety Summary Chapter 2
Caution Identifies information that, if not
heeded, may cause damage to the
Symetrix product or other equip
ment in your system.
Warning Identifies information that, if
ignored, may be hazardous to
your health or that of others.
CAPITALS Controls, switches or other
markings on the product'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.
Danger from loss of ground - If the pro-
tective ground connection is lost, all accessible
conductive parts, including knobs and controls
that may appear to be insulated, can render an
electric shock.
Proper power cord - Use only the power cord
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.
Stay out of the box - To avoid personal injury
or 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

3
531E 532E
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




















Fast Set-Up
This section is for those of you who are in too much of a hurry to read the rest of the manual. It provides
just enough information to get the Graphic Equalizer hooked up and working in your sound system.
Chapter 3
Set the INPUT LEVEL control at the unity
gain setting . This is noted as U at the
12:00 position.
Set all the graphic EQ slide potentiom-
eters at 0dB, center detent position.
Set LOW CUT control fully counterclock-
wise and the HIGH CUT control fully
clockwise.
Set the MODE switch to +/-12dB.
Connect equalizer to AC power.
Connect the audio inputs and outputs.
See chapter 5 if you need more informa-
tion.
Let er rip.
Now read the rest of this manual.




4
531E 532E
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Front Panel Controls
FRONT PANEL
Chapter 4
18K
HIGH CUT
±12dB
BYPASS
42K
3K 65K
MODE 0
-6
22
LOW CUT
50
U
INPUT
5K
115
6 260
8
∞
- +15
CLIP
10dB
0dB
POWER
-20dB
LEVEL CUT FILTERS
±6dB
-3
Input Level control - Use this control to
adjust the 531E/532Es input sensitivity. The
range is -∞(infinity) to + 15dB. You can do
three useful things with this knob:
1) Turn the knob down completely to mute
your sound system - this can be very useful
during troubleshooting, or if your console
lacks an output mute switch.
2) Turn it down a little to give yourself enough
headroom to make massive boosts in the EQ
section without clipping.
3) Turn the knob up a little to boost a low-
level input signal - this maximizes your signal
to noise ratio.
Note: This feature, like everything else on
the unit, will be bypassed if the 531E/
532E loses power or gets disconnected
from AC power.
Output Level Meter - The four segment LED
meter is designed to give you a quick, general
idea about the level of the 531E/532Es output.
The bottom LED at -20dBu is a signal
present indicator. The next two LEDs, at
0dBu and +10dBu show the activity of a signal
at nominal to somewhat hot line levels.
The top LED, labeled CLIP, will light when a
+20 dBu signal is detected at the input buffer
amp or output stage, though the 531E and
532E actually clip at +22dBu. Consider the
CLIP LED a slightly early warning light.
Note: If the INPUT LEVEL control is turned all
the way down and you send a very hot input
signal (greater than +20dBu) into the
equalizers input, the CLIP LED will illuminate
even though there will be no output signal.
This will occur because the input buffer amp,
which is before the INPUT LEVEL control, is one
of the points at which the CLIP
LED detects excessive signal
levels.
Low Cut Filter - Diagram 1
illustrates the 12dB per octave
low-frequency rolloff filter. This
filter is good for several things. It
protects the low-frequency drivers
in your sound system by removing
potentially damaging subsonic
audio material. This will also increase the
efficiency of the amplifiers - why make them
amplify signals that the speakers cannot
reproduce? It can also clean up an overly
muddy sounding mix or improve speech
intelligibility in announce systems by removing
excessive low-frequency audio material. The
range of this control is 6 Hz to 260 Hz.
High Cut Filter - Diagram 2 shows the range
of the 12dB per octave high-frequency rolloff
filter (3kHz to 65kHz). Use this control to
remove unwanted noise or hiss that is greater
in frequency than the highest frequency content
of the program material you are trying to
reproduce. This is especially pertinent to
speech reinforcement and paging systems.
Mode Switch - This space-saving, three
position toggle switch controls the cut/boost
range of the faders AND functions as an EQ
BYPASS when set in the middle position.
If you require very fine cut and boost control
for critical system voicing, put this switch in
the +/-6dB mode. Permanent installations such
as churches or performing arts theaters would
be a good place to use this mode.
The +/-12dB mode is most useful for concert
and club sound applications where quick (and
sometimes extreme) control is desired. This, of
course, will reduce the resolution of the fader,
but the 60mm, long-throw faders on the 531E
provide more than adequate resolution for
most applications. In addition, we have
adjusted the control taper so that the majority
of the fader throw is dedicated to the +/- 6dB
range, giving you greater resolution in that
crucial area.
t

5
531E 532E
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AUDIO PRECISION 531E vs 23 MAY 96 10:54:00
-20.00
-15.00
-10.00
-5.000
0.0
5.0000
10.000
15.000
20.000
AMPL(dBu)
20 100 1k 10k 20k
FREQ(Hz)
AUDIO PRECISION 531E vs 23 MAY 96 10:49:15
-20.00
-15.00
-10.00
-5.000
0.0
5.0000
10.000
15.000
20.000
AMPL(dBu)
20 100 1k 10k 20k
FREQ(Hz)
The Graphic Equalizer - The 531E/532E has
31 filter bands on ISO 1/3rd octave centers.
The lowest filter band is on 20hz, the highest is
20kHz. Note the dual cut/boost scale on the
side of the fader bank - the different scales
correspond to the +/- 6dB and +/- 12dB
positions of the MODE switch.
Applied correctly, the graphic equalizer is a
useful and powerful tool. It can make a
mediocre system sound good. It can make a
good system great. However, used incorrectly,
it can make even a great system sound terrible.
With this in mind, we would like to offer
some tips to get you started in the right
direction.
Tip #1 Always listen to the PA system with
the graphic EQ in bypass before you start
fiddling with the sliders because many
frequency response problems are actually
something else entirely. If something sounds
wrong, check your entire PA system for
proper hookup and performance BEFORE
you start working with the equalizer. For
example:
+12
0
16K10K 12.5K 20K
-12
+12
16K12.5K10K 20K
-12
16K12.5K10K 20K
0
8K5K4K 6.3K3.15K2K 2.5K1.25K800 1K500400315 630 1.6K
4K 8K6.3K5K3.15K2K 2.5K
4K 8K6.3K5K3.15K2K 2.5K
1.25K1K800500400315 630
1.25K1K800500400315 630
1.6K
1.6K
25020016010063 80 1254025 31.520
0
CH1
MODE
50
250160 20010063 80 125
25020016010063 80 125
4025 31.5
BYPASS
±12dB
CH2
20
4025 31.5
±12dB
BYPASS
MODE
20
0
50
50
+6
-6
+6
-6
±6dB
±6dB
+12
+6
20K16K12.5K10K
0
-6
-12
16K 20K10K 12.5K
8K6.3K5K4K3.15K2K 2.5K1.25K800 1K630500400315 1.6K
6.3K 8K4K 5K3.15K2K 2.5K1.25K800 1K500315 400 630 1.6K
250160 20010063 80 1254025 31.520
+12
+6
50
200160 25010063 80 125
±12dB
BYPASS
MODE 0
4025 31.5
-6
-12
20 50
+6
+3
-3
-6
+6
+3
±6dB
-3
-6
Diagram 1 - Low Frequency Rolloff Filter Diagram 2 - High Frequency Rolloff Filter

6
531E 532E
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mMake sure that all the speakers are
working properly. Check each driver within an
enclosure separately. Large sound systems may
have many identical drivers in an array,
making it hard to pinpoint blown, or out-of-
phase drivers by ear.
m Adjust your overall system gain structure
so that all of the components in the signal path
are operating at nominal levels.
m Check your cabling! The vast majority of
sound system problems are related to cables.
Intermittent connections, polarity reverses, bad
grounds, shorts, etc. are all examples of
problems that can manifest themselves as
frequency response problems. For instance,
if the cable feeding your stage left subwoofer
array is polarity reversed, causing the left
subwoofer array to be out-of-phase with the
right subwoofer array, you will percieve this as
a lack of adequate low end power. Obviously,
no amount of work with the graphic equalizer
will fix this problem. Of course, the larger the
system, the more there is to check. Be thor-
ough.
Tip #2 If your sound system uses an active
crossover, as almost all concert sound systems
do, always adjust the crossover before you try
any equalization. You will maximize the
performance of your system by precisely
matching the crossover settings to the require-
ments of your loudspeaker array. This can only
be done properly before you start working with
+12
+6
20K16K12.5K10K
0
-6
-12
16K 20K10K 12.5K
8K6.3K5K4K3.15K2K 2.5K1.25K800 1K630500400315 1.6K
6.3K 8K4K 5K3.15K2K 2.5K1.25K800 1K500315 400 630 1.6K
250160 20010063 80 1254025 31.520
+12
+6
50
200160 25010063 80 125
±12dB
BYPASS
M
ODE 0
4025 31.5
-6
-12
20 50
+6
+3
-3
-6
+6
+3
±6dB
-3
-6
the graphic EQ.
Tip #3 Whether you tune your system using
the pink noise/spectrum analyzer method, or
by playing music and using your ears, you
should always do this at roughly the same
volume that you expect to be running the
system during the actual show. This is impor-
tant because the frequency response of the
human ear varies with sound pressure level.
This phenomenon is well documented, first by
Fletcher and Munson (and their eponymous
curves) and later (and more accurately) by
Robinson and Dodson.
Tip #4 Cut and boost only at the frequency
desired (one at a time)- do not move entire
groups of sliders indiscriminately because this
leads to: The dreaded fader creep! No, this is
not a name for the guy who stands behind the
mixing console. Rather, it is the situation in
which you find yourself appyling huge
amounts of cut or boost using several (or
many) adjacent bands, yet it doesnt seem to
help fix the problem. A classic example of this
is the Disco Smile. This term refers to an eq
curve that looks like the one shown below.
The key to successful graphic equalization is
to identify the frequency imbalance problem
and do the absolute minimum amount of cut
or boost that will correct the problem.
Diagram 3 - The “Disco Smile”

7
531E 532E
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Rear Panel ConnectionsChapter 5
REAR PANEL
10 WATTS
MAXIMUM
AC INPUT
Q
UÉ AUX E.-U. PAR SYMETRIX INC., LYNNWOOD, WASHINGTON.
RÉFÉREZ TOUTE RÉPARATION À UN TECHNICIEN QUALIFIÉ.
AC Power Cord - The IEC-type AC power
socket on the 531E/532Es rear panel will
accept standard detachable power cords for the
US or Europe. However, make sure you know
what the operating voltage of the unit is before
you plug it in. If you are unsure of the units
operating voltage, or would like to change it,
please contact the factory or your nearest
qualified service center.
Failsafe Bypass Relay - The 531E and 532E
are equipped with a failsafe bypass relay to ensure that the units will pass audio signal in the event
of power failure. When AC power is connected, the relay routes the audio signal through the
equalizers signal path. If AC power is disconnected, or if the units internal power supply should
happen to fail, the relay connects the output jacks directly to the input jacks. This bypasses all
circuitry and ensures the continued operation of your sound system, albeit without equalization.
INPUT
UNBALANCED
BALANCED/
BALANCED
Inputs - The 531E and 532E are equipped with electronically
balanced, line level inputs - one XLR and one 1/4" TRS,
wired in parallel. The chart on the rear panel indicates the
pin/wiring configuration. This chart is also shown below.
Though it is theoretically possible to use both inputs at once,
we strongly recommend that you do not unless it is a dire
emergency. (and we mean dire...) It will not damage the
531E/532E, but we cannot say the same for the other units
involved. See appendix B for examples of adapter wiring.
OUTPUT
BALANCED/
UNBALANCED
BALANCED
Outputs - The 531E and 532E are equipped with servo-
balanced, line-level outputs - one XLR and one 1/4" TRS per
channel, wired in parallel. The chart on the rear panel indi-
cates the pin/wiring configuration. This chart is also shown
below.
Unlike the input jacks, you can use both output jacks simulta-
neously. The only caveat is that if you use one of the output
jacks unbalanced and the other balanced, make sure that the
unbalanced connection does not short either of the signal-carrying leads to ground. If you use a
standard 1/4" TS unbalanced plug in the 531E or 532Es 1/4" output, it will also unbalance the
XLR output connector. To avoid this situation, use a TRS plug in the 1/4" output and make sure
that the Ring is left unconnected (see appendix B for examples of adapter wiring.).
TIP
RING
SLEEVE
231
INPUT
21 3
TIP = HIGH(+) = PIN 2
RING = LOW(-) = PIN 3
SLEEVE = GND = PIN 1
TYPICAL BALANCED CONNECTIONS
OUTPUT
This chart (which is
screened on the rear panel
next to the INPUT and
OUTPUT connectors) indi-
cates the pin/wiring configu-
ration for the INPUT and
OUTPUT connectors.

8
531E 532E
/
Troubleshooting Chapter 6
There is no output signal.
Check input and output cables and
connections.
Determine that there really is a signal
coming from the source, and that it is
getting to the 531E/532E.
Distortion in the output signal.
Put 531E/532E into BYPASS. If
problem remains, unplug unit to
enagage the fail-safe bypass relay. If
problem still remains, check the audio
source.
Check the level of the input signal. Is
it overdriving the 531E/532Es input?
If so, reduce the incoming signal level.
Is the 531E/532Es clip indicator lit?
Is the incoming signal already dis-
torted?
Listen up stream from the 531E/
532E to determine that you are
feeding it a clean signal.
Are you using an EQ band or bands to
apply a lot of boost? If so, you may be
running out of headroom. Fix this by
lowering the input level control, or
reducing the amount of boost.
Buzz in the output.
Check input and output connector
wiring.
Check for ground loops between
interconnected system equipment.
Are all system components on the
same
AC ground?
Noise (hiss).
Unplug the 531E/532E to engage the
fail-safe bypass relay. If problem
remains, check your signal source.
Check input signal levels and input
level control settings. The input signal
may be too low in level. If so, boost
the incoming signal (if possible).
Solutions to
Common Problems
Is the input signal already noisy?
Listen up stream from the 531E/
532E to determine that you are
feeding it a clean signal.
Controls dont seem to have any effect.
Is AC power connected to the unit?
Since the 531E/532E use automatic,
fail-safe bypass relays, they will still
pass audio even when power is
turned off, though the controls will
have no effect.
Is the Mode switch in the correct
position?
The 531E/532E does not power up or does
not respond properly.
Consult a qualified service technician
or the Symetrix factory.
The 531E/532E is not plugged in, but works
great anyway.
Ok, you stumped us.