Symetrix 450 User manual

450
450 Dual Zone Priority Mixer
Users Guide

i
Table of Contents
450
Chapter 1 Introduction 1
Chapter 2 Operator Safety Summary 2
Chapter 3 Fast Setup 3
Chapter 4 Mic/Line Inputs 4
Chapter 5 Stereo Line Inputs 6
Chapter 6 Output Zone Master
Chapter 7 Priority Override Muting 9
Chapter 8 Applications 10
Chapter 9 Troubleshooting 12
Chapter 10 Specifications 13
Chapter 11 Warranty & Service 14
Appendix A Input/Output Connections 16
Appendix B Declaration of Conformity 1
Rev C.00, 6 July, 1999
Symetrix part number 53450-0C00
Subject to change without notice.
©1999, 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 photo-
copying, scanning, recording or by any information
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]

450
1
IntroductionChapter 1
The 450 Dual Zone Priority Mixer is designed for paging and music sound systems in clubs,
restaurants, hotels, conference facilities, houses of orship or any here multiple audio inputs
must be combined and distributed. There are t o mono mic/line inputs ( ith phantom po er and
lo frequency filters) and four stereo line inputs. Each input may be assigned to a stereo output
zone, a mono output zone or both.
Our unique hierarchical Priority Override structure permits the t o mic/line inputs and the first
stereo line input to mute the other (lo er priority) inputs assigned to the same zone. For example, in
a typical configuration, a paging microphone assigned to the stereo zone ill have priority over a
background music source (connected to line input 5-6) in that zone. A jukebox (connected to line
input 3-4) in the same zone ill have priority over the background music, but the paging signal ill
retain ultimate priority and force muting of both the jukebox and the background music henever
the page mic is used.
The 450's flexibility and simplicity make it the perfect choice for a ide variety of systems. By
accepting audio inputs from virtually any type of audio source and selectively routing to either the
mono or stereo output zone the 450 can save you time and money in the design and installation of
your next project.
Of course e recommend you read this manual cover-to-cover. You ll find the ans er to most of
your questions inside. If you have technical questions beyond the scope of this manual contact
our Customer Service Department at:
Phone:[phone]
Fax:[phone]
Email: [email protected]
RIGHT LEFTRIGHT LEFTRIGHT LEFTRIGHT LEFT
MIC/LINE IN 2 (PRIORITY 2)
IN
OUT
MIC
LINE
MIC PAD
INPUT SELECT INPUT SELECT
LINE
MIC
ZONE 1ZONE 2
SUPPLY ONLY.
OR PS-3E POWER
SYMETRIX PS-3
CONNECT TO
PARTS.
NO USER SERVICABLE
THIS UNIT CONTAINS
MANUFACTURED IN LYNNWOOD, WA, USA
OUT
IN
MIC PAD
(MONO)
(PRIORITY 3)
LINE IN 3-4
(MONO)
LINE IN 5-6
RIGHT LEFT
(STEREO)
ZONE 2
REMOTE CONTROL
ZONE 1
(MONO)
LINE IN 9-10 MIC/LINE IN 1 (PRIORITY 1)
(MONO)
OUTPUTS
450
DUAL ZONE PRIORITY MIXER
(MONO)
LINE IN 7-8
Front panel
Rear panel
OVERRIDE
PRIORITY
ZONE 2 OUT (STEREO)ZONE 1 OUT (MONO)LINE IN 9-10LINE IN 7-8LINE IN 5-6LINE IN 3-4 (PRIORITY 3)MIC/LINE IN 2 (PRIORITY 2)MIC/LINE IN 1 (PRIORITY 1)
450
DUAL ZONE
PRIORITY MIXER
UUUUUUUU
+15dB+15dB+15dB+15dB+15dB+15dB+15dB+15dB
∞∞
LOW BYPASS
MASTERMASTER
+15
0
-30
-15
+15
0
-15
-30
ZONE ASSIGNZONE ASSIGNZONE ASSIGNZONE ASSIGN
∞
GAIN
∞
GAIN
∞
GAIN
∞
GAIN
∞
GAIN
ZONE ASSIGN
∞
POWER
PRIORITY
OVERRIDE
BYPASS
LOW
ZONE 1
ZONE 2
ZONE 1
ZONE 2
ZONE 1
ZONE 2
ZONE 1
ZONE 2
ZONE 1
HIGH PASSZONE 2
RL
GAIN
HIGH PASSZONE 2
ZONE ASSIGN
ZONE 1

450
2
Operator Safety Summary Chapter 2
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 ords.
These are:
Note Identifies information that needs
extra emphasis. A Note generally
supplies extra information to help
you to better use the 450.
Caution Identifies information that, if not
heeded, may cause damage to the
450 or other equipment in your
system.
Warning Identifies information that, if
ignored, may be hazardous to your
health or that of others.
CAPITALS Controls, s itches or other markings
on the 450's chassis.
Boldface Strong emphasis.
Equipment Markings
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
No 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
The lightning flash ith arro head symbol ithin an
equilateral triangle is intended to alert the user of the
presence of uninsulated dangerous voltage ithin
the product s enclosure that may be of sufficient
magnitude to constitute a risk of electric shock to
persons. The exclamation point ithin an equilateral
triangle is intended to alert the user of the presence of
important operating and maintenance (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 e tension cord, receptacle, or other
outlet unless the blades can be fully
inserted.
ImportantSafetyInstructions
Please read and keep these instructions. Heed
and follo all arnings and instructions.
Install in accordance ith the manufacturer s
instructions.
Power Source This product is intended to
operate from a po er source that does not apply
more than 250V rms bet een the po er supply
conductors or bet een either po er supply
conductor and ground. A protective ground
connection, by ay of the grounding conductor
in the po er cord, is essential for safe operation.
Grounding The chassis of this product is
grounded through the grounding conductor of
the po er cord. To avoid electric shock, plug the
po er cord into a properly ired receptacle
before making any connections to the product. A
protective ground connection, by ay of the
grounding conductor in the po er cord, is
essential for safe operation. Do not defeat the
safety purpose of the grounding plug. The
grounding plug has t o blades and a third
grounding prong. The third prong is provided for
your safety. When the provided plug does not fit
your outlet, consult an electrician for replacement
of the obsolete outlet.
Danger from oss of Ground If the protective
ground connection is lost, all accessible conduc-
tive parts, including knobs and controls that may
appear to be insulated, can render an electric
shock.
Proper Power Cord Use only the po er cord
and connector specified for the product and your
operating locale. Use only a cord that is in good
condition. Protect the power cord from being
alked on or pinched, particularly at plugs,
convenience receptacles, and the point here
they exit from the apparatus.
Operating ocation Do not operate this equip-
ment under any of the following conditions:
explosive atmospheres, in et locations, in
inclement eather, improper or unkno n AC
mains voltage, or if improperly fused. Do not
install near any heat source such as radiators,
heat registers, stoves, or other apparatus
(including amplifiers) that produce heat. Unplug
this apparatus during lightning storms or hen
unused for long periods of time.
Stay Out of the Box To avoid personal injury (or
orse), do not remove the product covers or
panels. Do not operate the product ithout the
covers and panels properly installed. Only use
accessories specified by the manufacturer. Clean
only ith a damp cloth.
User-serviceable parts There are no user
serviceable parts inside the 450. In case of failure,
refer all servicing to the factory. Servicing is
required hen the 450 has been damaged in any
ay, such as hen a po er supply cord or plug
is damaged, liquid has been spilled or objects
have fallen into the apparatus, the apparatus has
been exposed to rain or moisture, does not
operate normally, or has been dropped.

450
3
1. Turn all front panel gain controls do n.
2. Make sure all Zone Assign buttons are
OUT.
3. Connect the 450 to AC po er.
4. Set all back panel s itches in correct
position. Take extra care to set the Mic/
Line s itch (found on Inputs 1 and 2
only) in the appropriate position.
5. Connect all the audio inputs and outputs
you need.
6. Set BOTH Priority Override adjust-
ments to BYPASS. To use this feature,
see Priority Override Muting in the
Operations section of this manual.
7. Assign the inputs to appropriate zones,
set the Zone Out Master to 12:00 (unity
gain), and turn up each input until the
sound source is at the desired loudness.
8. No read the rest of this manual.
Fast Setup
If youre in a hurry to get the 450 into your sound system and dont have time to thoroughly read
this manual, the follo ing steps ill probably be enough to get you started:
Chapter 3

450
4
Mic/Line Inputs
Front Panel
Zone Assign - Any input can be assigned to either the mono or stereo output zone, or both, or
neither. When either Mic/Line input is assigned to the stereo output zone, both left and right ill
be driven by the same signal. For the best signal to noise performance, leave the input unassigned
if not in use.
Highpass Filter - 12dB/Oct LF rolloff. 3dB do n at 115 hz. Use this to eliminate excessive p-
popping or room rumble from paging/announce mics. Even if you don t notice a problem, try
pushing this s itch any ay. It increases the efficiency of systems using ceiling mounted speakers
of the 70V variety, because it removes lo frequency material that the speakers probably can t
reproduce any ay. It ill help your amplifier to run cooler, dra less po er, and just maybe it ill
help to extend the life of the speaker.
Channel Gain Control - Gain range is -infinity to +15dB. Unity gain (indicated by the U symbol
on the front panel) at 12:00 position. This is no ordinary volume control. Well, actually it is.
Chapter 4
MIC/LINE IN 2 (PRIORITY 2)MIC/LINE IN 1 (PRIORITY 1)
UU
+15dB+15dB
ZO
∞
GAIN
ZONE ASSIGN
∞
ZONE 1
HIGH PASSZONE 2
GAIN
HIGH PASSZONE 2
ZONE ASSIGN
ZONE 1

450
5
Rear Panel
X R Input Jack - In order to fit all the inputs and outputs onto the 450's rear panel, e combined
the Mic/Line Input jacks into one balanced XLR connector that can handle both. This jack is ired
as follo s:
Pin 1 = (ground, shield)
Pin 2 = (high, +)
Pin 3 = (lo , -)
Most lo impedance, balanced microphones (and many line level sources) can plug directly into
these jacks, but some sources ill require adapters. See the chart in Appendix A for examples.
Caution Do not attempt to connect a high impedance, unbalanced micro- phone (these
usually, but not always, have a 1/4" phone jack attached to them) to either Mic/Line
input unless you first disconnect the phantom power.
INPUT SE ECT Switch - Push this s itch in to accommodate line level sources such as PBX
paging outputs, mixing consoles, automated emergency announce systems, etc. This bypasses the
mic preamp circuit and disconnects phantom po er from the XLR connector.
Note Make sure the Mic/Line input is not assigned to either Zone Output hen you push
the Mic/Line s itch because the phantom po er may cause a slight pop.
In the mic (out) position, the input signal is routed through the mic preamp and the phantom po er
is engaged. The preamp stage delivers approximately 40 dB of gain.
Warning Do not put this switch into the Mic position when feeding a line level signal into this
input (unless you enjoy re-coning speakers).
MIC PAD Switch - This decreases the gain of the mic preamp by 20 dB. Engage this s itch if the
mic level signal source tends to overload the input preamp stage, or you notice that the incoming
signal is so hot that you have to run the Channel Gain knob really lo . Typically, this happens
hen using high output condenser mics, or handheld, close-talked mics. As the name Mic Pad
suggests, this s itch does not affect the input gain hen the channel is operating in Line mode.
Phantom Power- Phantom po er is applied to the Mic/Line input only hen the mic/line s itch is
in the mic (in) position. If you ant to completely disconnect the phantom po er, please contact
Symetrix Customer Service.
MIC/LINE IN 2 (PRIORITY 2)
IN
OUT
MIC
LINE
MIC PAD
INPUT SELECT INPUT SELECT
LINE
MIC
OUT
IN
MIC PAD
MIC/LINE IN 1 (PRIORITY 1)

450
6
Rear Panel
Input Jacks - Line inputs 3-6 are equipped ith 1/4", TRS (tip-ring-sleeve), balanced, phone jacks.
They are ired as follo s:
Tip = (high, +)
Ring = (lo , -)
Sleeve = (ground, shield)
Line inputs 7-10 are unbalanced RCA-phono type jacks. They are ired as follo s:
Tip = (high, +)
Sleeve = (ground, shield)
Though you ll be able to plug most line level outputs directly into the 450, some sources may need
adapters. See Appendix A for proper iring.
Mono/Stereo Operation - Line Inputs 3-10 are arranged in stereo pairs; each pair is assigned to a
single gain control on the front panel. If you ant to use one of these inputs ith a mono source,
just insert a single plug into the jack labeled Left (mono) and leave the Right jack unconnected.
The left jack ill automatically feed both the left and right channels of the Zone 2 (stereo) output.
Stereo Line Inputs
Front Panel
Zone Assign - As you might expect, the Left and Right input signals are summed hen fed to the
Zone 1 (mono) output. This is done independently of the Zone 2 (Stereo) feed, hich keeps the
signals separate. As ith the Mic/Line inputs, maximize the unit s signal-to-noise ratio by leaving
all unused inputs unassigned.
Channel Gain - The ide gain range of this control (-infinity to +15dB) accommodates the variety of
input levels generically kno n as line level , including tape decks, CD players, console feeds, etc.
Unity gain is indicated by the u symbol on the front panel.
Chapter 5
LINE IN 9-10LINE IN 7-8LINE IN 5-6LINE IN 3-4 (PRIORITY 3)
UUUU
+15dB+15dB+15dB+15dB
+1
-1
-
3
ZONE ASSIGNZONE ASSIGNZONE ASSIGNZONE ASSIGN
∞
GAIN
∞
GAIN
∞
GAIN
∞
GAIN
ZONE 1
ZONE 2
ZONE 1
ZONE 2
ZONE 1
ZONE 2
ZONE 1
ZONE 2
RIGHT LEFTRIGHT LEFTRIGHT LEFTRIGHT LEFT
E
1 (MONO)
(PRIORITY 3)
LINE IN 3-4
(MONO)
LINE IN 5-6
(MONO)
LINE IN 9-10
O
)(MONO)
LINE IN 7-8

450
7
Output Zone Master
Output Jacks - The 450's outputs are electronically balanced, lo -impedance, and capable of
driving a balanced input to +22dBu. The output connectors are 1/4" Tip-Ring-Sleeve and you can
find iring and adapter examples in Appendix A.
Master Gain Controls These controls have the same gain range as the input channel gain controls
-infinity to +15dB. The U symbol at the knobs 12:00 position indicates unity gain hen the 450's
output is driving a balanced input. The 450 uses a differential output driver that drops the output
level by 6db hen connected to an unbalanced input. This does not adversely affect the audio
quality hatsoever and is easily fixed by increasing the output gain knob setting by 6dB.
Chapter 6
Rear Panel
Front Panel
Remote Control - There are t o ays to externally control the volume of the 450's Zone Outputs.
Both options render the front panel master gain control inactive.
Option #1 - The easiest method is the old volume-knob-in-a- all-plate. Use a 50k linear potentiom-
eter and ire it as follo s on the next page in diagrams 1 or 2.
The remote control cable is not carrying any audio signal, just DC control voltage. This means that
you can use a very long cable (up to 1000’) ithout degrading the 450's performance hatsoever.
To achieve this, you must use 20-22 gauge, three conductor plus ground cable and ire it accord-
ing to diagram 2.
Option #2 - If you re using a programmable remote control system that has the ability to supply an
external voltage to the 450, no problemo. Wire it as seen in Diagrams 3 or 4 on the follo ing page.
The dB/Voltage gain scale is 5dB/V, Unity gain = 11.5V. Note that the +15V control voltage
supplied by the 450 (on the tip of the TRS connector) is not used in this configuration. This is
okay, it on t hurt anything. In fact, you can save a little money on your remote cable by using one
conductor plus ground for short cable runs (see diagram 3) or t o conductor plus ground for long
runs (see diagram 4).
OVERRIDE
PRIORITY
ZONE 2 OUT (STEREO)ZONE 1 OUT (MONO)
UU
+15dB+15dB
∞∞
LOW BYPASS
MASTERMASTER
+15
0
-30
-15
+15
0
-15
-30
POWER
PRIORITY
OVERRIDE
BYPASS
LOW
RL
ZONE 1ZONE 2
RIGHT LEFT
(STEREO)
ZONE 2
REMOTE CONTROL
ZONE 1
(MONO)
OUTPUTS
A
L ZONE PRIORITY MIXER

450
8
Diagram 2
RING
TIP
SLEEVE
FOR LONG DISTANCE OR
NOISY ENVIRONMENTS
(OVER 100 FEET)
3 CONDUCTOR WITH SHIELD
SHIELD CONNECTED
AT PLUG END ONLY
OPTIONAL
6
K
0
4 RESIST
O
R
50K LINEAR
POTENTIOMETER
Diagram 3
Diagram 4
RING
TIP NOT
CONNECTED
SLEEVE
SLEEVE TO
GROUND
RING TO VOLTAGE SOURCE
RING
TIP NOT
CONNECTED
SLEEVE
FOR LONG DISTANCE OR
NOISY ENVIRONMENTS
(OVER 100 FEET)
2 CONDUCTOR WITH SHIELD
SLEEVE TO
GROUND
RING TO VOLTAGE SOURCE
Diagram 1
RING
TIP
SLEEVE
OPTIONAL
6K04 RESISTOR
50K LINEAR
POTENTIOMETER
Remote Control Wiring

450
9
Priority Override Muting
Priority evels - The term priority override refers to the 450's ability to selectively mute it's lo
priority inputs hen audio signal is present on it's high priority inputs. There are actually four
different levels of priority, assigned as follo s:
Input Priority Level
Mic/Line In 1 Priority One (highest)
Mic/Line In 2 Priority T o (not so high)
Line In 3-4 Priority Three (even lo er)
Line In 5-6, 7-8, 9-10 No priority
When audio is detected on a Priority input, all inputs ith a lo er Priority Level ill mute until
audio is no longer detected on the higher Priority Level input (see the diagram belo ). It s impor-
tant to note that the Priority Override Muting function is directly linked to an input s zone assign-
ment.
Priority Override Adjustment - This control is the trim adjustment found next to each Zone Out
Master level control on the 450's front panel (see the front panel dra ing on page 7). It varies the
trigger threshold of the Priority Override muting function. i.e. The muting function activates hen
the audio level on a Priority channel exceeds this setting. To disable the Override function for
either Zone Out, set the trim control to the Bypass position.
Note We recommend that you set the trigger threshold as lo as possible if you are using one
music source to mute another. An example of this is a restaurant/bar system that uses a
CD jukebox to automatically mute the TV/video feed. A lo threshold ill prevent the
lo priority input from un-muting during quiet musical passages.
Note In a paging system ith a live (i.e. no on/off s itches) paging mic, you may ant to set
the trigger threshold higher to prevent background noise from activating the muting
function.
Chapter 7
ZONE 1
MIC/
LINE 1 MIC/ LINE 2 LINE 3/4 LINE 5/6 LINE 7/8 LINE 9/10
ZONE 2
MUTING
LOGIC
MUTING
LOGIC
PRIORITY 1
PRIORITY 1
(STEREO)
(MONO)
PRIORITY 2
PRIORITY 2
PRIORITY 3
PRIORITY 3
NO
PRIORITY
ZONE 1
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASS
I
GN
ZONE 1
ASSIGN
ZONE 1
ASSIGN
ZONE 1
ASSIGN
ZONE 1
ASSIGN
ZONE 1
ASSIGN
NO
PRIORITY
OVERRIDE
OVERRIDE
PRIORITY
PRIORITY

450
10
The follo ing is a layout of a
typical restaurant/bar combination
system. When someone makes an
announcement, the announce
audio goes only to Zone 2 hich
e have dra n as a stereo sound
system in the bar area. The 450
mutes only the foreground music s
feed to that zone, leaving the Zone
1 (the dining room) music feed live.
It s like having t o separate mixers
in one chassis.
Two Zone Foreground Music with Paging
ZONE 1
DINING
ROOM
MIC/
LINE 1
PAGING MIC FORGOUND
MUSIC
MIC/
LINE 2 LINE 3/4 LINE 5/6 LINE 7/8 LINE 9/10
BAR
ZONE 2
MUTING
LOGIC
MUTING
LOGIC
PRIORITY 1
PRIORITY 1
(STEREO)
(MONO)
PRIORITY 2
PRIORITY 2
PRIORITY 3
PRIORITY 3
NO
PRIORITY
ZONE 1
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 1
ASSIGN
ZONE 1
ASSIGN
ZONE 1
ASSIGN
ZONE 1
ASSIGN
ZONE 1
ASSIGN
NO
PRIORITY
Applications Chapter 8
Mic and PBX Paging with Emergency Override
ZONE 1
MIC/
LINE 1
PAGING
MIC
MIC/
LINE 2 LINE 3/4 LINE 5/6 LINE 7/8 LINE 9/10
ZONE 2
MUTING
LOGIC
MUTING
LOGIC
PRIORITY 1
PRIORITY 1
(STEREO)
(MONO)
PRIORITY 2
PRIORITY 2
PRIORITY 3
PRIORITY 3
NO
PRIORITY
ZONE 1
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 1
ASSIGN
ZONE 1
ASSIGN
ZONE 1
ASSIGN
ZONE 1
ASSIGN
ZONE 1
ASSIGN
NO
PRIORITY
PBX
PREAMP
AUTOMATED
EVACUATION
ANNOUNCE
The reason that e included t o
mic/line inputs as the t o top
priority levels is to accommodate
the needs of industrial paging
systems. The follo ing diagram
sho s ho the Priority Override
Muting system handles multiple
paging sources. The paging mic
overrides PBX pages. Both of
these, ho ever, are muted by the
fire alarm/evacuation announce
system.

450
11
Meeting/Presentation Rooms with Remote Control
In meeting rooms, the 450 is flexible
enough to handle both speech
reinforcement and audio playback
at the same time, even if you re
using t o separate speaker
systems. In the diagram belo ,
note that the remote control jacks
allo the user to adjust the music
and mic volume separately from
ithin the meeting room.
Subgrouping with Remote Control
TAPED
MUSIC REMOTE
CONTROL
ZONE 1
MIC/
LINE 1
PAGING
MIC
MIC/
LINE 2 LINE 3/4 LINE 5/6 LINE 7/8 LINE 9/10
ZONE 2
MUTING
LOGIC
PRIORITY 1
(STEREO)
(MONO)
PRIORITY 2
PRIORITY 3
ZONE 1
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASS
I
GN
ZONE 1
ASSIGN
ZONE 1
ASSIGN
ZONE 1
ASSIGN
ZONE 1
ASSIGN
ZONE 1
ASSIGN
NO
PRIORITY
AUTOMATED
EVACUATION
ANNOUNCE
PRIORITY 1
PRIORITY 3
NO
PRIORITY
PRIORITY 2
CD
PLAYER
MUZAK
FEED
In the follo ing diagram , e
present an idea that you ill find
useful in hotels and convention
centers . The music sources (inputs
5-10) are assigned only to the zone
1 output. A patch cord connects
this output to Line Input 3, hich is
assigned only (this is important) to
Zone 2. The Zone 2 output is then
fed to the amplifier’s that drive the
speakers. A remote control,
conveniently located near the
paging mic, is connected to the
Zone 1 output. This configuration
gives the staff convenient control
over the music volume but leaves
the paging volume untouched. This
can be especially useful in systems
here the staff ants control over
the background music volume, but
the automated emergency an-
nounce system must al ays be
heard.
ZONE 1
MIC/
LINE 1
LECTURN
MIC MUSIC/
VIDEO REMOTE
VOLUME
CONTROLS
MIC/
LINE 2 LINE 3/4 LINE 5/6 LINE 7/8 LINE 9/10
ZONE 2
MUTING
LOGIC
MUTING
LOGIC
PRIORITY 1
PRIORITY 1
(STEREO)
(MONO)
CEILING
SPEAKERS
MUSIC
PLAYBACK
SYSTEM
PRIORITY 2
PRIORITY 2
PRIORITY 3
PRIORITY 3
NO
PRIORITY
ZONE 1
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 2
ASSIGN
ZONE 1
ASSIGN
ZONE 1
ASSIGN
ZONE 1
ASSIGN
ZONE 1
ASSIGN
ZONE 1
ASSIGN
NO
PRIORITY

450
12
Troubleshooting Chapter 9
There is no output signal:
Check the AC po er connections to the 450.
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 450.
Make sure that the input signal is assigned to Zone 1 or Zone 2 or both.
Distortion in the output signal:
Check the input signal. Is it overdriving the 450's input? If so, reduce the incoming signal level
or, in the case of microphone signals, use the 450's microphone pad.
Is the incoming signal already distorted? Listen up stream from the 450 to determine that
you are feeding it a clean signal(s).
Buzz in the output:
Check input and output connector iring.
Check for ground loops bet een interconnected system equipment.
Are all system components on the same AC ground?
Noise (hiss):
Check input signal levels and input level control settings. The input may be too lo in level. If
so, boost the incoming signal if possible. If the incoming signal is Mic level, make sure that
the Mic/Line S itch for that input is set to Mic .
Is the input signal already noisy? Listen up stream from the 450 to determine that you are
feeding it a clean signal(s).
The 450 doesn’t power up or doesn’t respond properly:
Consult a qualified service technician or the Symetrix factory.

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Specifications
Specifications
Architects and Engineers Specifications
The audio microphone and line mixer shall be a high performance unit occupying a single rack
space (1U).
The unit shall have two low impedance, balanced microphone/line inputs with connection via
female XLR. Each microphone/line input shall have a rear panel pushbutton which shall bypass the
mic preamp circuitry. Each input shall also have a switch to reduce the gain of the mic input by
20dB. Associated with each microphone input shall also be a front panel level control potentiom-
eter whose purpose is to establish the level of the microphone channel as it is mixed to either a
mono output zone, a stereo output zone, or both simultaneously. Each microphone input shall also
have a first order low cut filter with a 115Hz rolloff frequency.
The mic/line mixer shall have four stereo, line level inputs. Each input shall be assignable to either a
monaural output zone, a stereo output zone, or both. Associated with each line input shall be a
level control potentiometer whose purpose is to establish the level of the line level output signal as
it is mixed to either a mono output zone, a stereo output zone, or both simultaneously.
The 450 shall incorporate a four level priority muting system as follows. High priority inputs shall
mute or duck all lower priority inputs that are assigned to the same output zone when audio is
present at the higher priority input. There shall be a threshold control in each zone master section
which determines the minimum level of audio that will trigger the muting/ducking function. Priority
shall be assigned as follows: Mic/Line In 1 — Priority 1, Mic/Line In 2 — Priority 2, Line In 3-4 —
Priority 3, Line In 5-6, 7-8, 9-10 — No Priority.
Independent master output level controls shall be provided for both the monaural output zone and
the stereo output zone. LED peak meters shall indicate the actual output level regardless of the
nature of the load.
Independent means shall be provided to remotely control the output level of the mono output zone
and the stereo output zone. Rear panel jacks shall be provided to accept connections from standard
50K linear potentiometers for this purpose. When wired for remote control, the front panel output
zone level controls shall be disabled.
The mic/line mixer shall be a Symetrix, Inc. model 450 Dual Zone Priority Mixer.
Chapter 10
Note: The maximum operating ambient temperature is
25 degrees C.
Audio
Microphone Inputs Two, Low Impedance, Balanced
MicCommonModeRejection@1kHz,1VRMS >85 dB
Phantom Power +24V (10ma per input max)
Line Inputs Four,Stereo
Line Input Impedance >10kOhms,Balanced
Line Input Common Mode Rejection @ 1 kHz, 1V RMS >40 dB
Maximum Line Input Level +24 dBu Balanced, +18 dBu Unbalanced
Frequency Response, Any Input to Any Output±1 dB, 20 Hz to 20 kHz
Connections
Microphone Inputs XLR Female (pin2 high)
Line Inputs 1/4" TRS (tip is high), RCA-phono (Unbalanced)
Line Outputs 1/4" TRS (tip is high)
Remote Volume Control Inputs 1/4" TRS
Physical
Size(hwd) 1.72 x 19 x 6.5 inches, 4.37 x 48.26 x 16.51 centimeters
Weight 8 lbs (3.64kg) net
Electrical
Power requirements 117V nominal, 95 to 130V AC,
50 to 60 Hz, 15 watts
230V nominal, 165 to 255V AC, 50 Hz, 15 watts
Specifications subject to change without notice.

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Servicing the 450
Warranty & Service Chapter 11
450 Limited Warranty
Warranty
Following are the terms and limitations of the Symetrix warranty.
Symetrix, Inc. expressly warrants to the original purchaser ( Buyer ), subject to the terms and conditions set forth
below, that the roduct will be free from defects in material and workmanship as a result of normal commercial use
for eighteen (18) months from the date of shipment.
Some Symetrix products contain embedded software and may also be accompanied by control software intended to
be run on a personal computer. Said software is specifically excluded from this warranty.
Symetrix's warranty obligation is limited to the repair, replacement, or refund at Symetrix's sole discretion, of the
part or parts of the roduct which may thus prove defective in materials or workmanship within one year from date
of purchase under normal use and which our examination discloses to our satisfaction to be thus defective,
provided that Buyer gives Symetrix prompt notice of its warranty claim and satisfactory proof thereof.
Symetrix will make every reasonable effort to ensure that parts are available to support the repair of our products
under warranty. In the event that a product or component part thereof becomes obsolete, unavailable or irreparable,
Symetrix reserves the right to refund a prorated portion of the purchase price in full satisfaction of all warranty
claims.
In order to serve you better we require that the Buyer shall, prior to shipping roduct to Symetrix for warranty
service, contact Symetrix and secure a Return Authorization Number that shall be included with the returned
roduct. This will facilitate our efforts to keep track of your roduct and process your warranty repair as quickly as
possible. Buyer will prepay all freight charges to ship the roduct to Symetrix for warranty inspection and service.
This warranty is subject to Symetrix's inspection of the roduct at its facilities and, upon Symetrix's request,
satisfactory proof of purchase (dated copy of original retail dealer's invoice.)
Symetrix reserves the right to effect repairs to the product with reconditioned components/parts. roducts once
repaired under warranty will be shipped to Buyer freight prepaid by Symetrix via United arcel Service (surface) or
any similar shipper, to any location designated by buyer within the Continental United States. At Buyer's request
and expense roduct will be returned via airfreight. Outside the continental United States, repaired or replaced
products will be returned freight collect.
THIS WARRANTY IS EX RESSLY IN LIEU OF ALL OTHER WARRANTIES EX RESS OR IM LIED, ARISING
BY LAW OR OTHERWISE (INCLUDING, WITHOUT LIMITATION ANY OBLIGATIONS OF THE SELLER WITH
RES ECT TO CONSEQUENTIAL DAMAGES) INCLUDING THE WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR USE AND OF ALL OTHER OBLIGATIONS OR LIABILITIES ON OUR ART, AND WE NEITHER
ASSUME, NOR AUTHORIZE ANY OTHER ERSON TO ASSUME FOR US, ANY OTHER LIABILITY IN CON-
NECTION WITH THE SALE OF THE RODUCT. THIS WARRANTY SHALL NOT A LY TO THIS RODUCT
OR ANY ART THERE OF WHICH HAS BEEN SUBJECT TO ACCIDENT, NEGLIGENCE, ALTERATION,
ABUSE, OR MISUSE. WE MAKE NO WARRANTY WHATSOEVER IN RES ECT TO ACCESSORIES OR ARTS
NOT SU LIED BY US. THE TERM ORIGINAL URCHASER, AS USED IN THIS WARRANTY SHALL BE
DEEMED TO MEAN THAT ERSON OR COM ANY THAT ORIGINALLY URCHASED THE RODUCT.
This Symetrix product has been designed and manufactured for use in professional/industrial systems and is not
intended for other usage. This warranty only applies to Buyers using the roduct in professional/industrial systems.
With respect to others, including but not limited to consumers for personal, family, or household use, Symetrix
expressly disclaims all warranties, including but not limited to warranties of merchantability and fitness for a
particular purpose and the express warranties as otherwise provided herein.
Symetrix reserves the right to modify the design or make additions to, or improvements to, its product lines without
making similar upgrades to roduct purchased by Buyer. Symetrix does not authorize any third party, including any
dealer or sales representative, to assume any liability, effect any repairs or modifications to the roduct, or make
any additional warranties or representation regarding the roduct or roduct information on behalf of Symetrix.
Symetrix's total liability on any claim, whether in contract, tort (including negligence) or otherwise arising out of,
connected with, or resulting from the manufacture, sale, delivery, resale, repair, replacement or use of roduct will
not exceed the purchase price of the roduct or any part thereof which gives rise to the claim. In no event will
Symetrix be liable for any incidental or consequential damages including but not limited to damage for lost revenue,
cost of capital, claims of customers for service interruptions or failure to supply, and costs and expenses incurred in
connection with labor, overhead, transportation, installation or removal of products or substitute facilities or supply
houses as a result of roduct failure.
This limited warranty gives Buyer certain rights. Buyer may have additional rights under applicable law.

450
15
If you have determined that your 450 requires repair services and you live outside of the
United States, please contact your local Symetrix dealer or distributor for instructions on ho
to obtain service. If you reside in the U.S. then proceed as follo s:
Before sending anything to Symetrix, contact our Customer Service Department for a return
authorization (RA) number. The telephone number is [phone] or email:
[email protected]
In-warranty Repairs
To get your 450 repaired under the terms of the arranty:
1. Call us for an RA number.
2. Pack the unit in its original packaging materials.
3. Include your name, address, daytime telephone number, and a brief
statement of the problem.
4. Write the RA number on the outside of the box.
5. Ship the unit to Symetrix, freight prepaid.
We do not accept freight collect shipments.
Repairs made in- arranty ill cost you only one- ay freight charges. We'll prepay the return
(surface) freight.
If you send us your product in substandard packaging, e ill charge you for factory shipping
materials. If you don t have the factory packaging materials, please use an oversized carton,
rap the unit in a plastic bag, and surround it ith bubble- rap. Pack the box full of
Styrofoam peanuts. Be sure there is enough clearance in the carton to protect the rack ears
(you ouldn't believe ho many units are returned ith bent ears). We ill return the unit in
Symetrix packaging. Of course, if the repair is due to operator error, parts and labor ill be
charged. In any event, if there are charges for the repair costs, you ill pay for the return
freight. All charges ill be COD unless you have made other arrangements (prepaid, Visa or
Mastercard).
Out-of-warranty Repairs
If the arranty period has passed, you'll be billed for all necessary parts, labor, packaging
materials, and freight charges. Please remember, you must call for an RA number before
sending the unit to Symetrix.
Servicing the 450

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Input/Output Connections Appendix A
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

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Declaration of ConformityAppendix B
Declaration of Conformity
We, Symetrix Incorporated, 6408 216th St. SW, Mountlake Terrace, Washington, USA,
declare under our sole responsibility that the product:
450 Dual Zone Priority Mixer
to hich this declaration relates, is in conformity ith the follo ing standards:
EN 60065
Safety requirements for mains operated electronic and related
apparatus for household and similar general use.
EN 50081-1
Electromagnetic compatibility - Generic emission standard
Part 1: Residential, commercial, and light industry.
EN 50082-1
Electromagnetic compatibility - Generic immunity standard
Part 1: Residential, commercial, and light industry.
The technical construction file is maintained at:
Symetrix, Inc.
6408 216th St. SW
Mountlake Terrace, WA, 98043
USA
The authorized representative located ithin the European Community is:
World Marketing Associates
P.O. Box 100
St. Austell, Corn all, PL26 6YU, U.K.
Date of issue: 1 November 1995
Place of issue:Mountlake Terrace, Washington, USA
Authorized signature:
Dane Butcher, President, Symetrix Incorporated.

450