Speck EQ16-16 User manual

MODEL EQ16
16 CHANNEL - 3 BAND PARAMETRIC EQUALIZER
 Model EQ16-16
 Model EQ16-32
Reference Manual
speck
electronics

Speck Electronics makes no warranty of any kind with regard to this material,
including, but not limited to, the implied warranties of merchantability and
fitness for a particular purpose. Speck Electronics shall not be liable for errors
contained herein or for incidental consequential damages in connection with the
furnishing, performance, or use of this material.
This document contains proprietary information which is protected by
copyright. All rights are reserved. No part of this document may be
photocopied, reproduced, or translated into another language without the prior
written consent of Speck Electronics.
The information contained in this document is subject to change without notice.
Speck Electronics products are warranted to the original owner to be free of
defects in material or workmanship.
This warranty does not apply to incandescent lamps, slide potentiometers, or
any product subject to accident, misuse, neglect or failure to comply with
normal maintenance procedures or if the serial number has been defaced,
altered, or removed; nor will Speck Electronics accept responsibility for
damages resulting from improper installation, alteration or unauthorized parts
or repairs. If the product is modified by the customer without permission, the
customer agrees to pay for parts and labor necessary to remove the modification
before repair. The cause of the defect is in the sole judgment of Speck
Electronics.
Should a defect develop within one year of purchase from Speck Electronics or
an authorized dealer, Speck Electronics will supply the part or parts necessary
at no charge. Labor is covered in this warranty for a period of one year.
Outside service, repairs or pickups are not covered under this warranty.
Any item returned for warranty repair should be sent, if possible, in the original
packing container, prepaid to Speck Electronics, 925 S. Main Street, Fallbrook,
California, 92028. If in our opinion the packing container is improper for
return shipping, we reserve the right to supply a new container at a minimal
charge.
In the interest of improving Speck Mixers and related products; designs and
specifications are subject to change without notice. It should be mentioned that
if a change is necessary for any reason, we make every effort to document
that change and send an "update notice" to all customers at no charge.
First Printing - January 1993
Second Prnting - March 1998
Notice
Warranty
ii
Edition

iii
General ......................................................................................
Operator Safety Summary .........................................................
Power source .......................................................................
Grounding the product ........................................................
Use the proper power cord ..................................................
Use the proper fuse .............................................................
Panels and Covers ...............................................................
General Description ...................................................................
Standard Accessories .................................................................
Model PS3 power supply ....................................................
Rack mount adapters............................................................
Unpacking and Inspection .........................................................
Environmental Considerations ..................................................
Grounding ...........................................................................
Rack grounding ...................................................................
Repacking for Shipment ............................................................
General ......................................................................................
Mechanical Installation .............................................................
Physical Placement of Adjacent Equipment ..............................
Power Supply ............................................................................
Mounting location ...............................................................
Configuring the AC .............................................................
AC wiring chart....................................................................
Fuse chart.............................................................................
Connecting the Power Supply ....................................................
DC pin assignment...............................................................
Rack Mount Adapters.................................................................
Chapter 2 Initial Preparation
Contents
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Chapter 1 Introduction
Chapter 3 Installation
Contents

Installation ...........................................................................
Default Control Settings ............................................................
Cleaning ....................................................................................
Interfacing the Model EQ16 ......................................................
Things that can be interfaced ...............................................
Connecting to a balanced output..........................................
Connecting to a balanced input............................................
Things that cannot be connected...........................................
Connecting to a Mixer................................................................
3 Popular Mixers ........................................................................
Speck Electronics Xtramix...................................................
Samson MPL 2242 ...............................................................
Mackie CR-1604 ..................................................................
General.......................................................................................
Basic Theory of Equalizers.........................................................
Low-pass filter......................................................................
High-pass filter.....................................................................
Bandpass filter......................................................................
Front Panel Controls ...............................................................
General .................................................................................
Frequency sweep ..................................................................
Boost/cut...............................................................................
Bandwidth ............................................................................
Rear Panel Connectors.............................................................
Headroom and Boost/Cut Explained..........................................
General ......................................................................................
Start simple .........................................................................
Audio Cable ...............................................................................
Multipair wire harnesses .....................................................
Connectors .................................................................................
Proper AC Grounding ................................................................
Quality AC system ..............................................................
AC distribution ....................................................................
Clock noise and AC ............................................................
Safety earth connection .......................................................
Electronics earth ..................................................................
Proper Audio Grounding and Shielding ....................................
EMI and RFI ..............................................................................
Sources of EMI ...................................................................
Reducing EMI .....................................................................
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Chapter 4 Operation
iv
Chapter 5 Wiring and Other
Contents

1
Thank you for purchasing our Model EQ16 Sixteen Channel Equalizer.
This manual covers the operation of the Model EQ16-16 and Model
EQ16-32.
The Model EQ16 has operational features that are easy to understand
and you should be up and running in no time. If you are unfamiliar with
audio equipment or audio signal flow, it is recommended that you read
this manual. If you have any questions regarding the Model EQ16 or
any Speck product, do not hesitate to contact Speck Electronics. Our
phone number is [phone].
This product and its power supply are intended to operate from an AC
power source that does not apply more than 240 Volts RMS between the
supply conductors or between either supply conductor and ground.
The external power supply for the EQ16 is grounded through the
grounding conductor of the power cord. To avoid electrical shock, plug
the power cord into a properly wired receptacle before making any audio
connection to the equalizer. A protective ground connection, by the way
of the grounding conductor in the power cord, is essential for safe
operation.
Upon loss of the protective ground connection, all accessible
conductive parts, including knobs and controls that may appear to be
insulating, can render an electric shock.
Use only the power cord and connector that is supplied with your power
supply. The power cord must be in good condition.
To avoid a fire hazard, use only a fuse of the correct type, voltage rating
and current rating as specified on the chassis of the power supply and
this manual.
Refer to the section in this manual regarding specific details on fuses.
General
Power source
Operator Safety
Summary
Grounding the product
Use the proper power cord
Use the proper fuse
Introduction
Chapter 1 Introduction Section

Figure 1b. Rear Panel Layout
2
Figure 1a. Front Panel Layout
Chapter 1 Introduction Section

To avoid personal injury, do not remove the top cover from the power
supply, or the rear panel of the Model EQ16 and never operate the
external power supply without the cover properly installed. If it
becomes necessary to remove the rear panel of the EQ16 for service,
always unplug the AC power and disconnect the DC interface cable
before proceeding.
The EQ16 is available in two versions: The EQ16-16; 16 mono three
band equalizers, and the EQ16-32; 16 stereo three band equalizers. The
EQ16 may be connected virtually anywhere in the line level audio path
of professional equipment where equalization is required.
The Model EQ16 is a 3 rack space chassis that incorporates 16
independent channels of three band semi-parametric equalizers. Its
versatility and applications are limited only by your imagination. The
Model EQ16 is well suited in audio applications from professional
recording, sound contracting, public address, stage, or any application
where equalization is required.
Some of the many applications of the Model EQ16 is when interfaced to
the Speck Electronics Xtramix or any one of the many commercially
available recording mixers that lack the complete 3 sweepable bands of
the Model EQ16, or lack equalization altogether.
The Model EQ16 will accept a wide variety of signal levels. From the
wide range of levels developed from synths or samplers (typically
-20 dBu to +10 dBu) to the highest levels developed by professional
recorders (typically +4 dBu to +22 dBu).
Each channel of the Model EQ16 is divided into 3 bands; the low
frequency band, mid frequency band, and high frequency band. Each
band has 2 controls; the frequency sweep control and boost/cut control.
The Model EQ16 is supplied with an external rack mount regulated
power supply. The Model EQ16-16 (16 mono channel version) is
supplied with the Model PS3-0.8 power supply. The Model EQ16-32
(16 stereo channel version) is supplied with the higher powered Model
PS3-1.5 power supply.
Both versions of the PS3 power supply include a IEC power entry
connector, a 3 conductor AC power cord, and a 6 foot DC cable. The
DC cable has a 6 pin connector at one end that plugs into the power
supply, and a 6 pin connector at the other end that plugs into the EQ16.
This cable may be secured to the rear chassis of the EQ16 for a positive
connection.
Do not remove covers or panels
General Description
3
Standard Accessories
Model PS3 power supply
Chapter 1 Introduction Section

The Model EQ16 is supplied with a set of rack mount adapters. If the
intention is to mount the EQ16 in a standard 19" equipment rack, these
adapters must be mounted to the left and right sides of the mixer.
4
CAUTION!
IMPORTANT!
ALWAYS CHECK THE PROPER OPERATING
VOLTAGE BEFORE OPERATING THE MODEL
USE ONLY THE POWER SUPPLY THAT IS
SPECIFIED FOR YOUR PRODUCT.
Rack mount adapters
Chapter 1 Introduction Section

5
The Model EQ16 is delivered in a special, protective container and was
carefully inspected both mechanically and electrically before shipment.
It should be physically free of mars and scratches and in perfect
electrical order upon receipt. To confirm this, the product should be
inspected for physical damage that may have occurred in transit. Any
damage should be reported to your dealer or delivery company as soon
as possible.
The Model EQ16 will operate satisfactorily over a wide range of
ambient temperatures. The EQ16 will operate from 10 to 50 degrees C
and the external power supply will operate from 0 to 40 degrees C. If
the EQ16 is installed in an equipment rack that also contains heat
producing equipment such as power amplifiers or other power supplies,
adequate ventilation should be provided. This will prolong component
life and maximize operational stability.
While the internal circuitry of the EQ16 is fully shielded by the steel
chassis, installation should nevertheless be planned to avoid locating it
or any low level audio equipment immediately adjacent to power
amplifiers, power supplies, or any source of electromagnetic emissions.
To protect operating personnel, the National Electrical Manufacturers
Association (NEMA) recommends that the instrument panel and rack
cabinet be grounded. All Speck power supplies are equipped with a
three conductor power cord which, when plugged into an appropriate
receptacle, grounds the power supply.
The three conductor line cord and plug assembly is wired in
accordance with NEMA convention (line - black, Neutral - white, and
safety earth - green). Audio signal grounds and DC grounds from the
EQ16 are isolated from the AC safety earth.
When using the EQ16 and its power supply outside North America, it
may be necessary to adapt a different power cord for that specific
country.
Unpacking and
Inspection
Grounding
Environmental
Considerations
Initial Preparation
CAUTION! DO NOT REMOVE, DEFEAT, OR DISABLE THE
SAFETY EARTH TERMINAL ON ANY POWER
CORD. DO NOT USE A GROUND LIFT ON THE
POWER SUPPLY.
Chapter 2 Initial Preparation

Merely affixing the Model EQ16 into an equipment rack is no guarantee
that the product is making a reliable ground connection. The mounting
rails in the equipment rack should never be depended upon for a ground
connection.
The following information is provided as a general guide for
repackaging your Model EQ16 for shipment. If you have any questions,
contact your local Speck Dealer or Speck Electronics direct.
If the product is to be shipped to Speck Electronics for service or repair,
attach a tag to the product, identifying the owner and indicating the
service or repair to be accomplished. Include the model number and
serial number of the product. Place the product in the original container
if available. If the original container in not available, a suitable one can
be purchased from Speck Electronics.
If the original container is not used, wrap the product in heavy plastic
before placing in an inner container. Use plenty of packing material
around all sides of the product and protect panel faces with cardboard
strips. Mark shipping container with "Delicate Instrument" or "Fragile",
and insure the shipment for the proper amount.
Repacking For
Shipment
6
Rack grounding
Chapter 2 Initial Preparation

7
The following information should give you the basics on how to install
the Model EQ16 and Power Supply. The proper installation of the
Model EQ16 as a part of a larger system requires a clear understanding
of audio wiring, AC distribution, grounding, and shielding techniques.
When the EQ16 is being installed into a larger system it may be
necessary to retain the services of someone experienced in these matters.
Before the EQ16 may be placed into its normal operating position, it
will be necessary to install the rack mount adapters.
The Model EQ16 may be installed into any 19" wide equipment rack
that uses standard E.I.A. universal spacing. The EQ16 may be affixed to
standard E.I.A. rack rails using (4) 10-32 machine screws.
The location of the EQ16 should be such that the operator has a clear,
unobstructed view of the front panel from his normal operating position.
The unit should also be within easy reach of the operators normal
position in order to facilitate the use of the front panel controls.
Any device that emits a high EMI (Electro Magnetic Interference) or
RFI (Radio Frequency Interference) energy field should be treated with
suspicion. EMI is considered any unwanted signal which adversely
affects the operation of the equalizer or the mixing system. This subject
is discussed in Chapter 5.
Electronic equipment such as power amplifiers, power supplies
(especially wall mount type), video monitors, computers, certain synths
and samplers must be located away from the EQ16 and its associated
cables. It may be necessary to alter the positions of certain equipment
that you feel would cause buzzes or hums in your audio system.
The PS3-0.8 power supply is supplied with the EQ16-16 (16 mono
channel version), and the higher powered PS3-1.5 is supplied with the
EQ16-32 (16 stereo channel version).
If you happen to be installing both versions of the Model EQ16 into
your system, it is extremely important that the PS3-0.8 supply only
be connected to the EQ16-16 and the PS3-1.5 only be connected to
the EQ16-32.
General
Mechanical Installation
Installation
Physical Placement of
Adjacent Equipment
Power Supply
Chapter 3 Installation Section

The PS3 offers a variety of mounting options. The power supply may
be placed on any flat surface, permanently affixed to a flat surface, or
mounted on a single rack rail with the optional rack mount adapter.
One of the primary reasons that the power supply of the EQ16 is
external is to insure that the power transformer enclosed within the
power supply chassis maintains a safe distance from the active
electronics of the EQ16. For that matter, any power supply (especially
the small wall mount supplies), power amplifiers, or any strong power
field device should be kept at a reasonable distance from the EQ16. It is
also important to keep the above mentioned devices clear of all interface
cables, audio cables and harnesses.
The external power supply for the EQ16 does not provide an AC power
switch. It is recommended the power supply be plugged into an AC
outlet that uses a power switch.
The power supply should not be installed directly above or below the
equalizer. It is recommended that it be installed in the rear of the
equipment rack, providing that it remains at a reasonable distance from
the audio equipment and cables, and has adequate ventilation.
The power supply normally generates a small amount of heat during
operation. It is important that adequate ventilation is provided when
planning the mounting location.
The power supply may be wired to operate with 100 VAC, 120 VAC,
220 VAC, 230 VAC, or 240 VAC 50/60hz. Before applying AC power,
you should verify that the voltage setting on your power supply is
configured to match the AC requirements of your country. This
procedure should be performed and checked by a qualified technician.
Unless otherwise specified on the panel of the supply, the power supply
is wired for 120 VAC 50/60Hz operation and uses a North American
style AC plug.
To gain access to the inside of the power supply, it will be necessary to
remove the top cover. This is accomplished by removing the 4 screws
on the bottom of the power supply chassis. Make certain that the power
supply is unplugged before proceeding.
Mounting location
Configuring the AC
8
Chapter 3 Installation Section

There are 5 terminals available on the power transformer of the power
supply. The configuration of the five terminals determine the operating
voltage of the power supply. It is only necessary to change the black
(line) and white (neutral) AC wires. Do not attempt to remove or
change the Green AC safety wire or the multicolored wires used at
the DC terminals. It is recommended that you measure the DC
voltages at the DC connector before reconnection to the mixer.
The following chart represents the proper AC terminal configuration for
the Model PS3-0.8 and PS3-1.5 power supply.
The following chart represents the proper fuse rating for the Model PS3
power supplies. All fuses are 5 x 20mm Slow-Blow type.
Before connecting the DC power supply connector to the Model EQ16,
make certain the power supply is not plugged in.
The power supply interface cable is a 3 conductor wire with a square
plug on each end. Do not attempt to extend or modify this cable. Any
attempt to modify this cable could result in severe damage to the EQ16
or power supply.
To connect the power supply to the mixer, first fit the square plug into
the receptacle on the power supply. The connectors are keyed so they
will only fit in one direction.
AC wiring chart
Connecting the
Power Supply
9
Fuse chart
CAUTION! ALWAYS VERIFY THE PROPER OPERATING VOLTAGE
FOR USE AT:
JUMPER AT:
APPLY A.C. AT:
120 VAC
1 & 3
2 & 4
4 & 1
220 VAC
2 & 3
1 & 5
230 VAC
2 & 3
4 & 1
240 VAC
2 & 3
4 & 1
100 VAC
1 & 3
2 & 4
5 & 1
.75 AMP
.75 AMP
.375 AMP
.375 AMP
.375 AMP
100 VOLTS AC
120 VOLTS AC
220 VOLTS AC
230 VOLTS AC
240 VOLTS AC
MODEL PS3- 0.8
1 AMP
1 AMP
.5 AMP
.5 AMP
.5 AMP
100 VOLTS AC
120 VOLTS AC
220 VOLTS AC
230 VOLTS AC
240 VOLTS AC
MODEL PS3- 1.5
Chapter 3 Installation Section

Next, fit the square plug into the connector at the rear of the Model
EQ16. These connectors are also keyed to fit in only one direction.
Once the plug has been connected to the EQ16, it may be secured with a
cable tie to the adjacent cable tie holder.
The following chart represents the DC voltages available at the 6 pin
connector (Figure 2) on the Model PS3 Power Supply.
In order to install the Model EQ16 in a 19" equipment rack, it will be
necessary to attach the two rack mount adapters to the main chassis of
the Model EQ16. Each rack mount adapter is attached to the main
chassis with (3) 6-32 x 3/16" Phillips machine screws.
Position the adapters so the side with the small round holes match the
threaded holes on the sides of the EQ16, and the side with the oval
shaped holes are towards the front panel. Using a #1 Phillips
screwdriver, attach the rack mount adapters to the left and right sides of
the chassis with the 6 screws and tighten.
Before any attempt is made to operate the EQ16, it would be a good idea
to set all the controls to their neutral positions. This gives you a
reference point to work from when adjusting controls and switches.
All frequency sweep controls should be set to their full counter-
clockwise setting. All boost/cut controls should be set centered. All
pushbutton switches on the front panel should be set to the out position.
When any future reference is made to the controls or switches of the
Model EQ16, is will be assumed that they have been set to their neutral
positions.
The front and rear panels are a high quality painted surface and the panel
lettering is applied using a silkscreen printing technique.
Power supply DC pin
IMPORTANT! ONLY USE THE SHORT SCREWS THAT ARE SUPPLIED
WITH THE MIXER. USING LONGER SCREWS WILL
DAMAGE THE INTERNAL CIRCUITRY OF THE EQ16.
10
Rack Mount Adapters
Installation
Default Control
Settings
132
465
PIN 1 - DC COMMON
PIN 2 - MINUS 16.25 VOLTS DC
PIN 3 - N/C
PIN 4 - N/C
PIN 5 - N/C
PIN 6 - PLUS 16.25 VOLTS DC
Figure 2.
Chapter 3 Installation Section

Interfacing the Model
EQ16 Equalizer
To clean the front or rear panel, wipe the surface gently using a soft lint-
free cloth to avoid scratching the panel or markings. Paper towels are
not recommended. Commercially available window cleaner solutions
may be used; however, the solution should be applied to the cloth and
not the panel to avoid the seepage of liquid to the inside of the
enclosure.
The Model EQ16 is available in two versions: The EQ16-16; 16 mono
channels, and the EQ16-32; 16 stereo channels. Each channel of the
EQ16-16 has two jacks; one input and one output. Each channel of the
EQ16-32 has four jacks; left and right inputs jacks and left and right
outputs jacks.
Any channel of the EQ16-32 stereo version may be utilized as mono
channel by simply connecting to the left/mono input and left/mono
output jacks.
Connections to each equalizer channel should be made with standard
balanced tip , ring, and sleeve (TRS) 1/4" plugs as shown in Figure 3.
Switchcraft brand #297 or #597 plugs are recommended.
Virtually any line level signal may be connected to the inputs of the
Model EQ16; Synths and samplers, mixing consoles (patch points, line
inputs, effects returns, effects sends), multitrack DAT recorders, hard
disk recorders, analog tape recorders, cassette recorders, CD players,
external mike preamps, and effects.
Cleaning
IMPORTANT! DO NOT USE BRUSHES OR FEATHER DUSTERS TO
REMOVE DUST. THIS MAY CAUSE DUST TO FALL
INTO THE OPENINGS AROUND THE
PUSHBUTTON SWITCHES.
11
Things that can be interfaced
to the Model EQ16
Fig 3. Tip, Ring, sleeve (TRS) plug
Chapter 3 Installation Section

Due to the flexibility of the Model EQ16, there are many places it may
be interfaced - too many to enumerate in the manual. A basic rule to
follow when interfacing the EQ16 is that inputs connect to outputs, and
outputs connect to inputs. This rule applies regardless of the type or
brand of product that is interfaced to the EQ16. Each manufacturer has
their own recommendation for interfacing external equipment. Refer to
the operating manual that accompanies the equipment.
The channels of the Model EQ16 are line level, meaning that they may
be connected to any other device that operates at line level. The EQ16 is
also considered a unity gain device, which means that it has no gain.
The EQ16 will operate with line input levels from -30 dBu to a
maximum of +28 dBu. See Chapter 4 for a more complete explanation
of operating levels.
When connecting the EQ16 to an audio mixer, it is recommended that it
be connected to the patch points of the input channels. Patch points may
also be referred to as insert points or channel access points. Regardless
of their name, patch points exist exclusively for the access of devices
such as the EQ16, limiters, compressors, gates, etc. These
aforementioned devices are regarded as processing equipment and are
normally connected (inserted) into a single channel. Processing
equipment differs from effects devices in that effects devices are
connected into the send/return jacks and may be accessed from all
channels via the effects send controls.
12
General
Connecting the
Model EQ16 to a Mixer
Chapter 3 Installation Section

A few of the larger recording consoles that lack a patchbay may use two
jacks for the channel's insert points; one jack for insert output, and
another for the insert input. Most of the smaller rack mount mixers
mentioned in this manual utilize a stereo (TRS) jack for the insert points.
For these mixers it will be necessary to utilize a special "Y" cable with a
stereo plug at one end and two mono plugs at the other ends.
(See figure 5)
When patch points are not available, such is the case with many smaller
mixers, the source signal (synth/sampler or recorder) may be connected
directly to the inputs of the EQ16. The outputs of the EQ16 would then
be connected to the line inputs of the mixer.
It is recommended that interface cables be kept as short as possible and
only high quality cable and connectors be considered.
Power amp speaker outputs, microphones, guitar pickups, phantom
power supplies.
13
Things that cannot be
connected to the Model EQ16
Figure 5. "Y" Cable schematic
Chapter 3 Installation Section

There are no special requirements for installation and interface of the
EQ16 to the Xtramix except to use reasonable care in the layout of the
audio wires.
It is recommended that the EQ16 be installed directly above or below
the Xtramix. This will allow you to keep the cable lengths short,
thereby reducing the susceptibility to hums and buzzes caused by EMI
emissions.
The EQ16 may be connected to virtually any signal path of the Xtramix.
One choice is to connect any number of stereo synths into the stereo
inputs of the Model EQ16-32 and the respective outputs of the EQ16-32
to the first 16 stereo inputs of the Xtramix. The following illustrations
(Figure 6 and Figure 7) show two recommended methods of connecting
the EQ16 to the Xtramix.
A balanced 1/4" TRS to 1/4" TRS audio cable is required for each "EQ
Out" to "Xtramix In" connection to be made. If the EQ16-32 is used, it
would require 32 cables for connection to the Xtramix.
The EQ16 may also be interfaced to the 8 subgroup patch points for
overall equalization of the assign subgroups, or the effects returns for
equalization of up to 8 stereo effects devices.
A special cable will be required if the EQ16 is interfaced to the
subgroup insert jack. This cable should be wired with a stereo 1/4" TRS
plug on one end, and (2) mono 1/4" TS plugs on the other ends (See
figure 5a and 5b in chapter 3). The ring of the stereo plug is the
subgroup insert output, this connects to the EQ input. The tip of the
stereo plug is the subgroup return, this connects to the output of the
EQ16.
A complete set of interface cables necessary to connect the Model EQ16
to the Xtramix are available from Speck Electronics.
14
Interface to
the Xtramix Mixer
Chapter 3 Installation Section

15
Figure 6. Speck Xtramix - Application #1
Chapter 3 Installation Section

16
Figure 7. Speck Xtramix - Application #2
Chapter 3 Installation Section