Symetrix SX208 User manual

Symetrix
SX208
STEREO
COMPRESSOR/LIMITER
User Manual
Ver, 1.0 Ocl. 1, 1990
Seville, WAiiBtOS
m
mZQD>ZB2*25!)S
rAN20B*2B3*S501
«iSymc»h April 1992

Foreword
Thankyou for purchasingthe Symetrix SX208.
The following Information In this manual may
help you achieve optimum performance from
your Stereo Compressor/Llmlter.
Even If you are very experienced with signal
processing equipment and techniques, we
encourage you to read and make use of this
manual.
Anycommentsonourproductsorthlsmanual
are more thsui welcome.

Table of Contents
Section Page
1. Introduction 1
1.1 Product Description 1
1.2 Dynamic Range 1
1.3 Threshold 2
1.4 Compression and Limiting 2
2Connections, Controls and Switches 4
2.1 Block Diagram 4
2.2 Rear Panel Connections 5
2.3 Front Panel Controls and SwHches 6
3. Troubleshooting 8
4. Service Information 9
4.1 Return Aulhodzallon 9
4.2 ln*warranty Repair 9
4.3 Out-ot-warranty Reapair 9
5. SX208 Specifications 10
6. Limited Warranty 11
7. PCS Layout 12
8. 8X208 Schematics 13
-u-

1. Introduction
1.1
Product
Description
Tlie Symetrix SX208 Stereo Compressor/
LimiterIs aprecision dynamic range controller
Intended for use In professional audio applica-
tions.
Four front panel controls, and aprecise 3LED
threshold Indicator allow signal manipulation
to solve problems found in both studio and live
environments, while retaining ease of opera-
tion. Balanced or unbalanced signals may be
applied to the 1/4“ TRS InputJacks. Outputs
may be utilized as balanced or unbalsunced
signal connections.
The heart of the SX208 is built around an
industiy standard high peifonnance VGA en-
abling adynamic range In excess of llOdB
with atypical distortion of less than .03%.
Paging systems, recording, broadcast and re-
inforcement sound ^sterns are Just afew of
the areas where the Symetrix SX208 will ofler
flawless transparent operation handling awide
variety of gain reduction tasks.
1.2
Dynamic
Range
When dealing with audio signals, the term
“dynamic range" describes actual level
changes, or the range over which signals
fluctuate. The dynamic range of the human
voice, from a wisper to ashout Is well over
lOOdB. So amicrophone will convert the
sound pressure of avoice going from a wisper
to ashout Into an electrical output signalwith
adynamic range of well over lOOdB.
For signals to stay below distortion and above
noise, their actual dynamic range must be
kept within the speclfled dynamic range ofthe
circuits through which those signals flow.
Unfortunately, the actual dynamic range of
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real world signals often exceed the available
dynamic range of even the best equipment.
1.3
Threshold
1.4
Compression
&Limiting
The dynamic range of the best analog record-
ers Is around 70dB; still not quite enough
room for very wide dynamic range signals. In
order to keep the signals going to the recorder
well above its noise floor, and at the same time
not exceed It’s limit before distortion occurs,
signal processing Is sometimes neccessaiy to
"squeeze" the signal Into that slgnal-to-nolse
"window."
Often. In order to place high dynamic range
signals into acircuit ofnormal dynamic range
capability, acompressor or limiter Is used to
reduce signal dynamic range by setting an
upper limit on the signal peaks.
The threshold is the level at which adynamic
range processor’s activity begins. In opera-
tion, the dynamic range processor’s sensing
clcuitry constantly "looks at" the incoming
signal and compares It to areference level,
which Is called the threshold point. Compres-
sors and limiters respond when signals are
above threshold. The threshold point of the
SX208 Is internally set at -lOdB.
Compression and limiting are both derived
from the same signal processing famlty ofgain
reduction. The heart of this process Is based
on amplifier circuitry in which the gain Is
dependent on the signal level passing through
it. These ampUflers are knownasVGA's(Voltage
Controlled Ampllfler). By changing the gain,
based onsignal conditions, the dynamic range
of that signal can be automatically altered.
2
The amountofgainreductionIs determinedby
the RATIO control. The ratio is the number of
declbles ofchange in the Input level, compared

to the number of declbles of change in the
output level. For example, if the input level to
acompressorIncreasesby 5dB and the change
In output level is IdB, then the compression
ratio Is 5:1. Low ratios provide agentle aver-
aging of levels. As the ratio is Increased, the
compressor becomes alimiter. When limiting
occurs, you are actually determining a"cell-
ing,'* a hard cut oCT. 'lyplcatly limiters are set
with ahlgherthreshold, so they"stay out ofthe
way" until they are needed, and then clamp
down on the signal. In simple summary, use
compression for signal leveling. limiting for
protection from seriously high peaks.

2.2 Rear Panel Connectors
INPUTS:
Balanced:
1/4-
TRSJax.+18dBv
MAX.
Unbalanced:
1/4'
TSJax.+18dBv
MAX.

•IS
2.3 Front Panel Controls and Switches
6

7
Signal.

3. Troubleshooting
No gain reduction
Is the System switch depressed to
"In" position?
Is the Input gain control set too tow
for the present signal?
Distortion or Check signal at Input. Is It too high or
Clipping at distorted? Check the setting of Both
Output Output and Input gain controls (one at
atime checking the Output control
first). Turn each control counter
clockwise until the "clip" LED turns off.
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4. Service Information
4.1 Symetilx will service any of Its products, no
Return matter when it was manufactured or what
Authorization condition It’s In. However, no goods will be
accepted without aReturn Authorization
number.
BEFORE 8END1NO ANTTHINa TO BTMSTRIX. CAIX
FOR AN R/A NUMBER. JUST ASK. WE'LL OLADLT
QIVBTOUONBI CAIL(208)3S2-3SBBWBBKDATB. S
AM TO 4PH PACIFIC TIME.
4.2
In-Warranty
Repairs
To get your unit fixed:
1.Call for an R/A number.
2. Pack the unit in Its original packaging
materials
3. Put the R/A number on the outside of
the box.
4. Ship it to Symetrix freight pre-pald.
Just do those four things, and repairs made
in-warranty wilt cost you only the one-way
freight fee. We’ll pay the return freight.
However, If you send it to us in some kind of
flimsy non-Symetrlx packaging we’ll have to
charge you for proper shipping materials. We
won't return the unit in anything but the
original Symetrix packaging. And ofcourse. If
the problem turns out to be operator Inflicted,
youll have to pay for parts, labor and regular
UPSshipplngcharges. ChargeswlllbeC.O.D.
(and we do mean CASH on delivery).
4.3
Out-of-
Warranty
Repairs
We’ll gladly service any Symetrix product,
any time. If the warranty period is passed
you'll be blUed for all necessary parts, labor,
packaging materials, as well as any appli-
cable freight charges.
Remember, you must call for an R/A
number before you send the unit to
Symetrix.
9

5. SX208 Specifications
impedatM
Max Input lavtl
CMRR
Eieclionically balanced
3000unbal. 600nbal.
20dBm
irdSm
Impedance
Max level Into GOOnbal.
Max (aval Inlo 600ft unbat.
int*io«o:
20Hi-20)(Hi -40/-1dB
Pr*«u«ney ItoeiMnM
16VAC, 200ma (Symelrlx PS-2 lor 1 lOVAC opeiallon.
PS-KPIot220VACopatation)
P«w«r R«i|ulr*mentt
eonlTAle Syatem Bypa», Input Gain, Rallo,
fiea^ Time. Output Gain
OmnMtor* Inputs and Outputs; TR$ 1/4’ nicna Jax
^]itirile*l 1
^W-F|OiilPanll”'easWjtVT5’H ••
v-f'pSibs*

6. Limited Warranty
llie Symeiiix SX208 i« deiltncd and manuftcuied for ute in prafeanonal and iiudio audio
ayatcmi. Symettix. Ine,. wananii ihai lh« SX308 manufactured by Symetiu, when properly
iniuUed, uied and maiiuained »accordance with iniinictlona contained in the manufeauter*!
opetator't minuil, will perform accordini to the tpeclTicationi act forth in the opetaior’i manual.
Symeiiixeaprcfilywarranti ihi(SX208willbefrcefiomdafeeuin material and wotkmanihipfor
one (l)year. Symeiiix’ obli|iUoiii under thia warranty will be liiniied to tepaiiinf and leplidng,
at Symetiix’ option, the pan or pant of the SX20B which prove defective in material or
worlminihipwithin one(l)yearffomihedaieofpurchaae,provided that the BuyeriiveaSymelria
prompt notice ofany defect orfailuia and aaiiafactory proofthereof. Producta mty be relumed by
Buyer only after eReium Auihorixatlon number (RA)hii beenobtained from Symetiix and Buyer
will prepty all fiei|hi chattel to return any praducii to the Symetiix facioiy. Symetiix teieivea
the right to inipect any pioducu which may be the lubjectof any wairanty claim befom lepair or
lepltoememitcanicdout. Symctiixmiy.atilioption.re<)uii«proofofiha original daieofpuichaie
(datedcopyoforiglnaiiculldealir'iinvdce). Pinal delennlnaiianofwaiTaniycovengelieiiidely
wiihSymetrix, Pioducia rcpalied under warranty wUIbereiuinedfielghl prepaidvia United Parcel
SeivlcobySymeirlx.loinyloctilonwiihiniheConUnenUlUniiedSiiiei. OuiaidetheContlnental
United Slatei, product! will be returned freight collect.
TKtroMoootowAtnAKmiAMmLBUorAU.oTKinwAitAKnu,winn»R oRAUwninxN,
ixrnui. latrLtnoox frAtvronv. evMEriti, ore iirnucLr ducumiany iMPLtto wakkan-
TIU.INCl.tHHNORTNtUPDR ArARTICULtR rUlfOU Ok MUCHANrAIILnir. IVMtTSIX, INC**
WAMtAKIY OlttOATWN AND >Um-| RIMIDIU HkhtUNDtR AkClOULY AND UCLUSIVILV Al
tTAnDMUBlN.
'nieSymetrixSX2MiedMignedandmmureciuiedforuielnpro(ciiionilanditudioeudioayiiana
endianotintendedforotheruaige. Widiteipecttoptodueupuichiiedbyconiumenforpeiaonal,
femily or houaehoid uae, Symeirix EXPRESSLY DISCLAIMS ALL IMPLIED WARRAN*
TIES, INCLUDING BirrNOTLlMITBDTO WARRAffTIES OFMERCHANTABILITY
AND FTTNESS FOR APARTICULAR PURPOSE.
11111 limited wimnty, with ell leimi. condiilona, limiiiikmi end dlaelaimcri act foith herein, ahall
extend to the originel purcheier and anyone who purchiiii the product within the apecified
warranty period.
Wirnniy Reginrailon mual be completed end mailed to SymetrU, Inc. within thirty (30) dayiof
the dawofpurchaae.
Symelfiadoei noteuihoriuioyihlrdpeny. including any dealerorialeatepieienuiive.loaiaume
any liiUlIiy or mike any iddiiionel werrantiei or repreaentatian tegerding Ihia product perform-
ance on behalf of Symeirix.
Thia limited wetraniy givei the buyer certain righta. You may have additional righii provided by
applicable lew.
LIMITATION OF LIABILITY
The total liabiUty of Symeirix, Inc. on any claim, whether in contract. Ion (including negligence)
orothctwiaeariiingoutof, connected with, orieiul(ingfromihemanufictuK,aeledeliveiy,ieiale,
repair, Rplacemenl or uae ofany product will not exaed the price allocable to the product or part
thereof wHdi givea rile to the elaim. In no event will Symeirix, Inc. be liable for any incidental
or coniequentiiidamagaa including but not limited to damage for loll of revenue, coat ofeaptal,
claimi ofcuiiomen for lerviceiniemiptiona orfailure to aupply, and cotta and expenieiincumd
in connection with labor, overhead, lranfpoiiatton,iniuUalion or removal ofproduct! or lubiiitute
facililiea or aupply ioukh.
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01990 Symetrix.Inc.
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