Symetrix 425 - Introduction

IN
+10
GAIN (dB)
+20
0
BYPASS
BYPASS
+12.5 +5 +15
+5 2
RATIO (X:1)
-10
10SLOW
1
-2.51.3 2.5
THRESHOLD (dBu)
THRESHOLD (dBu)
-10
FAST
BYPASS
-40
SLOW
-25 +10
-20
DUAL STEREO
STEREO
LINK
THRESHOLD (dBu)
BYPASS
+5
DUAL MONO
-5 -30
RELEASE
FAST
IN
GAIN (dB)
+10
+20 BYPASS
0
BYPASS
+12.5 +5 +15
+5 2
RATIO (X:1)
10
-10 1
SLOW
-2.5
1.3 2.5
THRESHOLD (dBu)
-10
THRESHOLD (dBu)
BYPASS
FAST
SLOW
-40
+10 -25
-20
THRESHOLD (dBu)
BYPASS
+5
-5 -30
RELEASE
FAST
RELEASE RELEASE
OUT
0VU CLIP-10 -20 -3
LIMIT
-6 -9 -12 -2
COMPRESSOR
-4 -6 -10 -12 -8 -25 -15 -6 -12 -2 -18
EXPANDEROUT
0VU CLIP-20 -3
LIMIT
-10 -6 -9 -12 -2
COMPRESSOR
-8 -6 -10 -12 -25 -15 -2 -6 -12 -18
EXPANDER
-4
1. Introduction
The Symetrix 425 is a dual channel compressor/limiter/expander. The two channels may be
operated in dual-mono mode, or in stereo mode. In stereo mode, both channels receive
identical control signals, which minimizes image shifts caused by unequal gains in the two
channels.
At Symetrix, we feel that the 425 represents the distillation of our 15 years of signal
processing experience into a product that is at once versatile and easy to use without having
important controls removed in the interest of simplicity. The 425 is unique because its
processor sections are always in-line. There is no selector switch to select between expander,
compressor, or limiter. Now you can expand the low-level parts of a signal to improve its
signal-to-noise ratio, then apply compression to add punch and density and still have the
security of a peak limiter for overload protection. We call this approach to total level control
IDP or Integrated Dynamics Processing.
IDP also means powerful, streamlined controls that make the 425 easy to learn and quick to
set up, even with three types of processing in one rack space. Each section has the controls
that you need to respond to any audio situation fast. Individual LED meters show you what's
going on inside each section.
The 425 is Listed by Underwriters Laboratories Inc. (UL). Samples of this product have been
evaluated by UL and meet the applicable UL Standards for Safety.
In the final analysis, Integrated Dynamics Processing means clean, quiet sound that meets
professional demands in any situation. High-quality components and a minimalist signal path
make the 425 exceptionally transparent.
1.1 About this manual
We recommend that you read this manual from cover to cover. Somewhere between the
confines of the two covers you should find the answers to most (98%) of your questions, both
technical as well as musical.
If you're in a hurry (like most of us), or if you really don't believe that someone could write a
decent owners manual that you can read and understand, then do us both a favor and read
section 6, "Fast First Time Setup." This section will help you get connected, tell you what the
knobs do, and send you on your way.
This manual contains the following sections:
Chapter 1. Introduction: introduces the 425 and this manual.
Chapter 2. Using the 425: describes how to use the 425. Covers installation, signal levels,
input and output impedances, and physical features.
Chapter 3. Technical Tutorial: a basic and not-so-basic discussion of signal levels, input and
output impedances and connection polarity.
Chapter 4. Front Panel Overview: a brief look at the controls and switches located on the front
panel of the 425.
Chapter 5. Rear Panel Overview: a brief look at the rear panel of the 425.
Chapter 6. Fast First Time Setup: is the setion to read if you can't wait.
Rev 2.0, 10/29/93
1-1