Audio Control EQL User manual

EQUALIZER/LEVEL MATCHER
22410 70th Ave. W., Mountlake Terrace, WA 98043
Phone [phone] • Fax [phone]
www.audiocontrol.com
®
making good stereo sound better
®
®
OWNER’S MANUALOWNER’S MANUAL
OWNER’S MANUALOWNER’S MANUAL
OWNER’S MANUAL
tm
Concert Series

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Concert Series Owner’s Manual
Quick Installation InfoQuick Installation Info
Quick Installation InfoQuick Installation Info
Quick Installation Info
Refer to Figures 4, 5, and 6 (on pages 9, 10, and
11) when installing the EQL Equalizer.
The unit is shipped from our factory with
the Programmable Frequency Match filter
module set at 30 Hz (see page 18 to change
this).
For information on other system applica-
tions or related topics, please read further.
TT
TT
Table of Contentsable of Contents
able of Contentsable of Contents
able of Contents
Introduction ....................................1
Description ......................................4
Installation ......................................8
Upgrading A Factory
(OEM) System ................................16
Making Your Own Programmable
Frequency Match Modules ............18
Troubleshooting ............................20
Warranty .......................................22
Specifications ................................24

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We design, test, and build each EQL Equalizer
right here in the misty rain forests1of the
Pacific Northwest. When you look inside the
rugged two-piece steel chassis, you’ll find we
use only premium electronic parts and gold-
plated RCA jacks.
It all adds up to a product that will provide
you with many years of listening enjoyment
and will literally outlast your vehicle.
Congratulations!Congratulations!
Congratulations!Congratulations!
Congratulations!
You have purchased one of the most exciting
and innovative audio products available for
your car stereo system – the AudioControl
EQL Equalizer/Level Matcher.
The EQL can make any system sound better.
Even if you have followed the true path of
enlightenment and are having your new EQL
professionally installed, it doesn’t hurt to
read this manual. There’s nothing but reruns
on the tube anyway!
The EQL carries on a great tradition started
back in 1985, when we introduced the origi-
nal EQL. Since then, AudioControl has gone
on to win numerous awards and collect
many glowing reviews for its innovative
autosound products. We have learned a great
deal about cars, stereos, and acoustics over
the years. All of this has been poured into the
new EQL to give you the tools to make your
car stereo the envy of all your pals.
1
Introduction
1
At last count, we see the sun only 129
days each year, so we use the abundant
indoor hours doing what we do best –
improving and inventing audio
products – besides, it keeps us from
going insane.

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Concert Series Owner’s Manual
äDual Bandwidth Equalizer – 13 bands
The dual bandwidth design of the EQL
concentrates more control in the lower
bass frequencies where the interior of an
automobile causes problems. The higher
frequency controls are spaced on octave
centers to give you complete control up
to 16,000 Hz. No simple dash-mount
equalizer gives you this kind of flexibility.
äLevel Matching
True standards in car stereo are hard to
find. Every manufacturer has a slightly
different interpretation of things. The
input and output level controls on the
EQL bring everything together. Now any
head unit can be connected to any ampli-
fier and the will system sound great.
äBalanced Input
The EQL takes noise rejection a step
further than the average by incorporating
balanced differential input circuitry. By
looking at the output from your source
unit in a different way the EQL can reject
up to 60 dB of radiated noise.
äProgrammable Frequency Match Filter
Our exclusive Programmable Frequency
Match (PFM) filter system brings out the
best in any system. A modular program-
mable low-cut frequency filter allows the
system installer to easily customize the
bass roll-off to match any speaker design.
Unruly subwoofer boxes can finally be
brought under control.
2

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äHigh Level Inputs
The EQL is so flexible that you don’t even
need to have pre-amp outputs on your
deck to enjoy the benefits of total control.
Speaker level signals can be run directly
into the EQL, equalized and level-
matched to use any aftermarket amplifier
or crossover with your system. There are
no limits.
IMPORTIMPORT
IMPORTIMPORT
IMPORTANTANT
ANTANT
ANT
For maximum product performance, noth-
ing is better than a professional system instal-
lation. Your AudioControl dealer has the
training and tools to take care of the job
quickly and without the anxiety of drilling
holes in your car. If you are just a dyed-in-
the-wool do-it-yourselfer, then this manual
should provide all the info you need to
successfully make music with the EQL.
The Most ImportantThe Most Important
The Most ImportantThe Most Important
The Most Important
Instruction Of AllInstruction Of All
Instruction Of AllInstruction Of All
Instruction Of All
FILL OUT AND SEND IN THE WARRANTY
CARD! Also, save the invoice or sales slip as
proof of purchase. These actions will protect
your investment and allow us to better help
you with any service-related questions.
3
Introduction

Concert Series Owner’s Manual
Figure 1.Top panel
layout for EQL
Equalizer/Level Matcher.
4

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DescriptionDescription
DescriptionDescription
Description
We’ve created the EQL Equalizer/Level
Matcher to make any system sound better.
This Performance Match™ Component2
features straightforward connections and
easy-to-adjust equalizer and level controls. To
learn more, read on.
Equalizer and Input/Output LevelEqualizer and Input/Output Level
Equalizer and Input/Output LevelEqualizer and Input/Output Level
Equalizer and Input/Output Level
Controls and IndicatorsControls and Indicators
Controls and IndicatorsControls and Indicators
Controls and Indicators
The top panel contains all equalizer controls,
input/output controls, and system indicators.
The equalizer controls are grouped by channels
in ascending frequencies from left to right, as
shown in Figure 1 on the previous page.
Each equalizer control provides 12 dB of boost
or cut for each channel. The Input Gain con-
trols allow you to adjust the Left or Right Input
gain over a range of ± 18 dB. Output attenuators
provide up to 30 dB of gain trim. The top panel
2
Our line of Performance Match Components takes the guess-
work out of creating the best-sounding system by “matching”
autosound components to your vehicle. For more information,
see page 21.
also includes several indicators to confirm
power and help set output levels.
äHALF OCTAVE BASS EQUALIZER – six
half-octave bass equalizer controls for
each channel with frequency centers at
31.5, 45, 63, 90, 125, and 180 Hz.
äOCTAVE EQUALIZER – seven full octave
equalizer controls with frequency centers at
250 and 500 Hz; and 1, 2, 4, 8, and 16 kHz.
äINPUT GAIN – variable gain controls to
adjust Left and Right Input levels.
äOUTPUT LEVEL CONTROLS – output
attenuators for Left and Right Outputs.
äINPUT MAXIMIZED – indicator for set-
ting the proper input gain. When this
light flickers you have juust the right
amount of input gain.
ä2 VOLT OUTPUT – indicator for monitor-
ing output level to detect and set a 2 volt
level.
äPOWER – indicator confirms power is
reaching the EQL.
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5
Description

Concert Series Owner’s Manual
Connections and Equalizer BypassConnections and Equalizer Bypass
Connections and Equalizer BypassConnections and Equalizer Bypass
Connections and Equalizer Bypass
The front panel contains power and input/
output connections, as well as an equalizer
bypass button, as shown in Figure 2 (above.)
äHIGH LEVEL INPUT – Our handy plug for
connection of speaker outputs from a
deck or factory stereo.
äEQUALIZE IN/OUT – Press in to engage
the equalizer settings on your EQL.
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Figure 2. Front panel layout for EQL
Equalizer/Level Matcher.
6
äLINE LEVEL INPUT – RCA jacks for con-
nection of low-level stereo signals from a
head unit.
äOUTPUT – RCA jacks for connection of
EQL outputs to the inputs of an amplifier.
äREMOTE/+12/GROUND - Another handy
plug for power connections of your
Remote Turn-On lead, +12 Volts, and
Power Ground.
HighLevel
Input
L R
+ – – +
Equalize
In
Out
LineLevel
Input
L R Output
L R RemoteGround
+12

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Programmable FProgrammable F
Programmable FProgrammable F
Programmable Frequency Matchrequency Match
requency Matchrequency Match
requency Match
Filter Module and Ground IsolationFilter Module and Ground Isolation
Filter Module and Ground IsolationFilter Module and Ground Isolation
Filter Module and Ground Isolation
Selector (Inside)Selector (Inside)
Selector (Inside)Selector (Inside)
Selector (Inside)
The Programmable Frequency Match filter
module, as well as the Ground Isolation
Selector, are internal and can be accessed by
removing the four top screws and lifting the
top panel off the base, as shown in Figure 3
(also see Figure 8 on page 19). Be sure to turn
off the power before you open the EQL.
We ship each EQL with the Programmable
Frequency Match filter set at 33 Hz. Refer to
page 18 for information on how to create
your own custom PFM module.
250 Hz
6
0
-6
+12-12
6
0
-6
+12-12
500 Hz
6
0
-6
+12-12
6
0
-6
+12-12
1 KHz
6
0
-6
+12-12
6
0
-6
+12-12
2 KHz
6
0
-6
+12-12
6
0
-6
+12-12
4 KHz
6
0
-6
+12-12
6
0
-6
+12-12
8 KHz
6
0
-6
+12-12
6
0
-6
+12-12
16 KHz
6
0
-6
+12-12
6
0
-6
+12-12
Left
Right
31.5 Hz
6
0
-6
+12-12
6
0
-6
+12-12
45 Hz
6
0
-6
+12-12
6
0
-6
+12-12
63 Hz
6
0
-6
+12-12
6
0
-6
+12-12
90 Hz
6
0
-6
+12-12
6
0
-6
+12-12
125 Hz
6
0
-6
+12-12
6
0
-6
+12-12
180 Hz
6
0
-6
+12-12
6
0
-6
+12-12
Left
Right
Half Octave Equalizer
Left
Right
Made in
America
Dual-Bandwidth Graphic Equalizer,
Programmable Frequency Match Filter,
Transformer Isolated DC/DC Power Supply
22410 70th Avenue West
Mountlake Terrace, WA 98043
206-775-8461
Serial Number
Output Status
Overload
2VoltOptimum
Power
0
-6
-12
6
12
-18 +18
0
-6
-12
6
12
-18 +18
Output Level
Input Gain
PFM Module
Located Inside
Line Level
Input
L R Output
L R
High Level
Input
L R
++
--
Out
In
Equalize
Remote Ground
+12
A
Performance Match
Component
Series II
0
-
0
-
Octave Equalizer
Figure 3. Removing the four top screws and lifting
the top panel provides access to the Programmable
Frequency Match filter module and Ground
Isolation Selector.
7
Description

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Concert Series Owner’s Manual
InstallationInstallation
InstallationInstallation
Installation
We strongly suggest you have the EQL pro-
fessionally installed, but if you are doing it
solo this section lists the procedures you’ll
need to install the EQL in your vehicle.
Before you begin we suggest you read the
next few sections to plan the type of system
you want.
System ApplicationsSystem Applications
System ApplicationsSystem Applications
System Applications
The EQL Equalizer/Level Matcher is quite
versatile. Use it to put together a simple
single-amplifier system, as shown in Figure 4
on page 9. Or better yet, add a couple of our
other fine components, and you are on your
way to building a great 2-way or 3-way
system, as shown in Figures 5 and 6 (on pages
10 and 11).
Installation PrecautionsInstallation Precautions
Installation PrecautionsInstallation Precautions
Installation Precautions
äDo not mount the EQL Equalizer/Level
Matcher where it will be exposed to outside
elements or extreme temperatures. Avoid
areas that are subject to extreme road vibra-
tion or shock. The front bumper is definitely
out-of-bounds.
äSelect an installation site that provides short
cable runs for minimum pick-up of engine
noise and RFI (radio frequency interference).
Keep RCA cables together, away from
speaker wires or power cables.
äAt the proposed installation site, make sure
the holes you plan to drill will not hit the
fuel tank, fuel lines, brake lines (under
chassis), or go through any electrical wiring.
äUse high-quality, fully-shielded RCA cables.
äPlan on a single-point grounding scheme
that is common to grounded parts of the
system. Use no less than 16-gauge stranded
copper wire for the ground connection.
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8

Figure 4. Wiring diagram for EQL Series II in a
single amplifier system.
Installation
9

Concert Series Owner’s Manual
Figure 5. this wiring diagram shows a 3-way system
that uses an EQL with an ESP-2 Spatial Restoration
Processor and a 4XS used as a 3-way Crossover.
10

Figure 6. Wiring diagram shows an EQL with an
AudioControl System90 Powered Signal Processor
in Bi-Amp Mode.
Installation
11

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Concert Series Owner’s Manual
WARNINGWARNING
WARNINGWARNING
WARNING
Before installation, turn off the
power to the head unit or radio and
disconnect the negative (-) lead of
your vehicle’s battery.
Mounting the EQLMounting the EQL
Mounting the EQLMounting the EQL
Mounting the EQL
1. Select a permanent mounting site for the
EQL. Make sure you observe the Installa-
tion Precautions listed on page 8.
2. Position the unit and use either a felt-tip
pen or spring-loaded center punch tool to
mark locations for the four mounting
holes.
3. Drill a small pilot hole at each marked
location.
4. Secure the EQL with self-tapping screws.
Connecting the EQLConnecting the EQL
Connecting the EQLConnecting the EQL
Connecting the EQL
1. Connect +12 Vdc and Ground from the
vehicle’s electrical system to the corre-
sponding +12 and GROUND terminals on
the EQL. Also connect the Remote turn-
on signal from the head unit to the RE-
MOTE terminal.
2. Connect a set of RCA cables from the
head unit Left and Right outputs to the
LINE LEVEL INPUT (LEFT and RIGHT) on
the EQL.
DO NOT CONNECT OUTPUTS AT
THIS TIME!
NOTE: For high-level signals, splice speaker
cable onto the radio’s speaker wires and connect
to the HIGH LEVEL INPUT (Left and Right).
3. On the EQL, set all equalizer controls to
the flat (i.e.,“0”) position. Set the INPUT
GAIN controls for minimum gain
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(i.e.,“-18”). Set all OUTPUT LEVEL controls
for maximum attenuation (i.e.,“- ∞”). Press
the EQUALIZE button IN.
4. Reconnect the vehicle’s negative (-) bat-
tery lead and proceed to the next section.
AA
AA
Adjusting the EQLdjusting the EQL
djusting the EQLdjusting the EQL
djusting the EQL
1. Turn on the head unit or radio. On the
EQL, you should see the (red) POWER
indicator illuminate. If not, check the
power connections, and try again. A test
light or digital multi-meter works great
for this.
2. Play a favorite tape or CD with consistent
music and turn up the volume control on
the head unit or radio to maximum level.
NOTE: Since the outputs are not connected, you
won’t hear any sound at this point.
3. Adjust the INPUT GAIN control until the
yellow INPUT MAXIMIZED starts to
flicker. Now back the control off until the
LED goes out.
4. Next, start the trackoverso that you are
referencing the same musical informa-
tion as in step 3. Adjust the OUTPUT
LEVEL until the 2 Volt Output light is
flickering steadily. If you find that you
have turned the OUTPUT LEVEL all the
way up without the 2 Volt Output light
coming on, you may leave this control at
“0” (or its fully clockwise position.)
5. Turn down the volume and power off the
head unit or radio.
6. Connect the EQL outputs according to
your system plan.
Installation
13

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Concert Series Owner’s Manual
are in a real hurry, you can set the equal-
izer by ear.
10. Listen to the vocals and instruments, and
trying cutting the frequencies in the mid-
bass (90 to 250 Hz) and mid-range (2 to 4
kHz) spectrum. The mid-bass response is
usually a problem area due to standing
waves caused by sound resonating in the
passenger compartment. The mid-range
frequencies are most sensitive to the ear
and usually need to be brought down a
bit.
11. Continue listening and try boosting the
low bass frequencies in the 31.5 to 63 Hz
area. Usually this area needs help due to
design limitations of smaller woofers and
loss of bass in cassettes.
AA
AA
Adjusting the EQL (cont’d)djusting the EQL (cont’d)
djusting the EQL (cont’d)djusting the EQL (cont’d)
djusting the EQL (cont’d)
NOTE: Consult the amplifier owner’s manual
for information on setting its input sensitivity.
If adjustable, set each amplifier to accept a
signal between 1.0 and 2.0 volts (1000 and 2000
mV). This may be a minimum setting on your
amp. Don’t worry, the EQL can still drive it to
full volume. If your Amp cannot accept 2V you
may need to turn the output level down a bit.
7. Play the same tape or CD (preferably one
containing a variety of acoustic instru-
ments).
8. With the deck’s volume set to a normal to
half-way listening position (i.e., about
one-third on), adjust the OUTPUT LEVEL
controls, if necessary, to get the system
playing at a comfortable level.
9. A third-octave real time audio analyzer is
the ultimate tool for getting the best
sound quality from your new EQL. If you
14

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Installation
NOTE: If the (yellow) OVERLOAD indicator
comes on, something is boosted too much.
Either bring down the suspect frequency control
or adjust the INPUT GAIN controls to reduce
the overall gain.
12. As a final check, press the EQUALIZE
switch OUT and IN to compare the sound
with and without equalization. Try
different program sources and make any
final adjustments.
Using a Real Time Audio Analyzer (RTUsing a Real Time Audio Analyzer (RT
Using a Real Time Audio Analyzer (RTUsing a Real Time Audio Analyzer (RT
Using a Real Time Audio Analyzer (RTA)A)
A)A)
A)
For a really well-balanced system, we highly
recommend using a Real Time Analyzer (like
the AudioControl SA-3055) to adjust your
vehicle’s sound system. This tool is especially
helpful in performing the initial adjustments
for multi-amplifier installations.
Balancing a system “by ear” should be per-
formed as fine-tuning after using a Real Time
Analyzer, since our ears adapt very quickly to
any new frequency adjustments.
In fact, if you listen to a badly-adjusted sys-
tem long enough, it will actually start sound-
ing pretty good. Only later, when your hear-
ing “refreshes” and your buddies come to
audition your new system, will you realize
how far off the mark Def Leppard really is!
Now. . . do yourself a big favor and ask an
authorized AudioControl dealer about this
professional sound-balancing option.
AudioControl SA-3055 Third-Octave Real Time
Audio Analyzer
15

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Concert Series Owner’s Manual
Upgrading A FUpgrading A F
Upgrading A FUpgrading A F
Upgrading A Factoryactory
actoryactory
actory
(OEM) System(OEM) System
(OEM) System(OEM) System
(OEM) System
Replacing a factory (OEM3) radio gets harder
each model year. Besides the non-standard
sizes, new models even feature volume and
tuning controls imbedded right in the steer-
ing wheel! It’s great for convenience, but
tough on the knuckles. It seems the boys in
Detroit and Japan want to make sure you
don’t throw out the original radio and re-
place it with some better model.
In all fairness, today’s crop of factory radios is
better. So rather than lose those nice steering
wheel volume controls, we’ve come up with
a way of improving your sound system by
using the High Level Inputs on the EQL and
the speaker leads from your factory radio, as
shown in Figure 7 on page 17.
3
OEM stands for Original Equipment Manufacturer, which used
to mean that a car manufacturer actually built and installed
each radio. Nowadays, a factory radio is made by an aftermarket
company for installation by the car manufacturer.
It’s as simple as moving the wires from the
speakers to the EQL. Don’t worry, the EQL is
designed to effortlessly handle the higher
signal levels coming from the factory radio,
without a trace of overload or added distor-
tion.
16

17
Upgrading Factory Systems
Figure 7. Wiring diagram shows
a factory (OEM) system
upgraded with the EQL and an
AudioControl System90
Powered Signal Processor to
create a superlative 2-way
system.

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Concert Series Owner’s Manual
7200
Frequency (in Hz)
EXAMPLE – For a 25 Hz filter, the
formula yields a resistor with a value of
7200
25
NOTE: Use only resistors having a tolerance of
five percent or better (i.e., 5%, 2%, etc.).
WARNINGWARNING
WARNINGWARNING
WARNING
TURN OFF THE SYSTEM BEFORE CHANG-
ING THE MODULE, OR ELSE SOMETHING
IN YOUR SYSTEM WILL BE DAMAGED!
CAUTION: The Programmable Frequency
Match Module must always be installed, even
if you are not using the filter. Failure to do so
may damage the EQL.
Making YMaking Y
Making YMaking Y
Making Your Ownour Own
our Ownour Own
our Own
Programmable FProgrammable F
Programmable FProgrammable F
Programmable Frequencyrequency
requencyrequency
requency
Match ModulesMatch Modules
Match ModulesMatch Modules
Match Modules
The EQL comes with an 18 dB per octave
Programmable Frequency Match low-cut filter
module already set to 33 Hz. This will act as a
subsonic filter, protecting your woofers. If you
have large woofers (i.e., 12" or 15"), you may
want a lower frequency module. With smaller
woofers (i.e., 6" or 8"), use a higher frequency
Programmable Frequency Match module.
Additional modules with pre-set frequencies
are available from an authorized AudioControl
dealer, or you can create a custom low cut filter
module by using the following formula4:
4
For more details, read our — (HEY! Not another #%*&% plug
disguised as a #%*&% footnote!) — ok, OK, OKAY! — We’ll make a
deal with you. Send us ten bucks, and we’ll send you the whole
set of Tech Papers and Tech Notes (which includes our Techni-
cal Note #1005 Crossovers Modules). And you won’t have to
read another tiny footnote — unless you want to.
= Resistor Value (in kohms)
= 288 kohms
18