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The ART Model 311
Precision Stereo 2-Way Active Crossover with Subwoofer Output
USER’S GUIDE
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TABLE OF CONTENTS
Introduction ........................................................................................... 3
Installation ............................................................................................. 4
AC Power Hookup ............................................................................... 4
Analog Audio Connections .................................................................. 4
Safety Precautions .............................................................................. 4
Controls ................................................................................................... 5
Power Switch ....................................................................................... 5
Low Output Level Control .................................................................... 5
Low Cut Filter Switch .......................................................................... 5
Crossover Frequency Control ............................................................. 5
High Output Level Control.................................................................... 6
Phase Switch ....................................................................................... 6
Sub Output Level Control .................................................................... 6
Subwoofer Frequency Control ............................................................. 6
Connections ........................................................................................... 7
XLR Input Jacks (Rear)........................................................................ 7
¼” Input Jacks (Rear) .......................................................................... 7
¼” Output Jacks (Rear)........................................................................ 7
Operation ............................................................................................... 8
Warranty Information .......................................................................... 10
Service .................................................................................................. 11
311 Specifications ............................................................................ 12
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INTRODUCTION
Thank you for purchasing an ART 311 - and congratulations: You now
own one of the most versatile crossovers available. Offering a superb level
of sound quality, the 311 circuit design, combined with a straightforward
user interface, quickly and easily gives you access to all of its features.
The Model 311 has been carefully designed, engineered and
manufactured to provide you with years of great sound and reliable service.
You’ll find it useful for pa systems for live sound reinforcement, public
address, karaoke and other various signal processing applications.
General Overview
The Model 311 is a fourth order Linkwitz-Riley Stereo 2-Way electronic
crossover with additional subwoofer output. Each channel of the 311
crossover splits the frequency of an input signal into two separate signals,
which may then be sent to amplifiers, or other signal processing equipment
in a sound system.
FEATURES:
• Balanced XLR and ¼” inputs
• ¼” Outputs
• 4-pole Linkwitz-Riley filter design (24dB/octave)
• Phase Reverse Switch on each channels High Output
• Switchable Low Cut (30Hz) filters on each channel and subwoofer
• Wide crossover frequency range (250Hz to 6kHz)
• Independent output level controls for each output
• Low noise circuitry
• Fully shielded all-steel chassis
• Internal AC power supply with standard IEC connector
• Designed and developed in the USA
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INSTALLATION
The 311 may be used in a wide variety of applications and
environments. Enclosed in a rack-mountable, all-steel enclosure, the
unit is designed for continuous professional use. Mounting location is
not critical. However, for greater reliability we recommend that you not
place the unit on top of power amps or other sources of heat.
AC POWER HOOKUP
The 311 has an internal power supply designed to operate at 115
VAC @ 50 to 60 Hz. Units manufactured for use outside the United
States of America have been modified to comply with the required
electrical specifications.
Before plugging the 311 into the main AC line, make sure that all of
the equipment following the crossover outputs, are turned off or all of
the outputs are turned down.
ANALOG AUDIO CONNECTIONS
Audio input connections to the 311 are balanced XLR (Pin 2 = Hot
(+), Pin 3 = Cold (-), Pin 1 = Ground) and ¼” phone plug (Tip = Hot (+),
Ring = Cold (-), Sleeve = Ground). All output connections are
unbalanced ¼” (Tip = Hot (+), Sleeve = Ground).
SAFETY PRECAUTIONS
Warning: To avoid the risk of shock or fire, do not expose this unit to
moisture. Refer all servicing to qualified personnel. Do not remove the
metal cover; there are no user-serviceable parts inside. When
applicable, only use the power adapter that came with this unit or one
obtained from ART’s Customer Service Department.
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CONTROLS
POWER SWITCH
The power switch applies and removes power to the Crossover. Make
sure all equipment after the 311 is either off or the outputs are turned
all the way down before turning on or off the 311.
LOW OUTPUT LEVEL CONTROL
Each channel of the 311 has a Low Output Level control. These
controls are used to trim the output levels to the Low Output jacks on
the rear of the unit.
They cover the range of –30dB to +10dB of output gain trim, as
indicated on the front panel. In most cases you would set them to 0dB,
for flattest response from the Crossover. You can use these controls to
compensate for amplifier gain variations or efficiency of your speakers.
LOW CUT FILTER SWITCH
The Low Cut switch activates a 30Hz high pass filter. There is one for
each of the Low Outputs and 1 for the Subwoofer Output. This filter is
a 2-pole Butterworth design (12dB/octave). Its response reduces
spurious subsonic frequencies, which tightens up the low end and
helps to protect your amplifiers and speakers.
CROSSOVER FREQUENCY CONTROL
Each channel of the 311 has a crossover Frequency control to set
the crossover point for the high and low frequencies. All frequencies
below the set frequency will be sent to the Low output and all
frequencies above the set frequency will be sent to the High output.
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The main crossover filters are 4-pole Linkwitz-Riley designs
(24dB/octave). This yields a sharp rolloff to help protect speakers and
the outputs sum to a flat response.
HIGH OUTPUT LEVEL CONTROL
Each channel of the 311 has a High Output Level control. These
controls are used to trim the output levels to the High Output Jacks on
the rear of the unit.
They cover the range of –30dB to +10dB of output gain trim, as
indicated on the front panel. In most cases you would set them to 0dB,
for flattest response from the Crossover. You can use these controls to
compensate for amplifier gain variations or efficiency of your speakers.
PHASE SWITCH
The Phase switch is used to switch the polarity (invert the phase) of
the signal going to the High Outputs. Normally you would leave this
switch in the Norm position. Putting the switch in the Invert position
may be done to help correct audible phase related problems.
SUB OUTPUT LEVEL CONTROL
This control is used to trim the audio output level to the Subwoofer
Output Jack on the rear of the unit. This signal is used to provide extra
bass via a mono subwoofer in your system.
SUBWOOFER FREQUENCY CONTROL
The Subwoofer Frequency control sets the crossover point for signals
going to the Subwoofer Output. For this function, both of the input
channel signals are combined and frequencies below the set frequency
will be sent to the Subwoofer Output. This is in addition to the normal
signals that are sent to each of the channels other outputs.
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CONNECTIONS
It is easy to interface the unit with a wide variety of equipment. The rear
panel has balanced XLR and ¼” inputs as well as unbalanced ¼” outputs.
XLR INPUT JACKS (REAR)
The XLR input connections are balanced and follow the AES standard
for wiring: Pin 1 = Ground, Pin 2 = Hot (+), Pin 3 = Cold (-). This input
parallels the ¼” inputs.
¼” INPUT JACKS (REAR)
The ¼” input connections are balanced with Tip = Hot (+), Ring = Cold
(-), and Sleeve = Ground. This input directly parallels the XLR input.
¼” OUTPUT JACKS (REAR)
The ¼” Output jacks are unbalanced. Tip = Hot (+) and Sleeve =
Ground. They are used for sending signals to amplifiers, or other
unbalanced configurations.
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OPERATION
The following guideline refers to a P.A. system, but the same basic
ideas apply to a home recording setup or a Hi-Fi system.
A stereo 2-way sound system is typically set up as follows: Separate
high frequency (horn or tweeter) and low frequency (bass) cabinets are
used for each side (left and right) of the sound system. The crossover
is used to split each side of the stereo signal into two frequency bands,
which will feed separate power amplifiers. This arrangement
accomplishes two things: it allows the proper frequencies to be routed
to the proper speaker cabinets and it allows the amplifier to produce
power more efficiently to the speakers it is driving.
It is very important that you use caution when selecting the
crossover points for any system. Refer to the documentation that
came with your speaker cabinets for information on their proper
frequency ranges. This is especially important for high frequency
horns; damage may occur from sending lower frequencies than
specified into the drivers!
Signal Flow
In most situations, the crossover is the last piece of equipment in the
signal chain before the power amplifiers. Signal flow is as follows:
From the output of the mixer to an equalizer (Sometimes, for system
protection, a limiter is placed between the mixer outputs and the
equalizer, or after the equalizer.) From the equalizer to the crossover.
From the crossover to the power amplifiers. From the power amplifiers
to the speaker cabinets.
Here are some tips to help you with your initial setup.
1. Set all level controls to their full counter-clockwise position (-30dB.)
2. Connect the outputs of your mixer (or equalizer) to the inputs of the
311. If stereo, Channel One is Left.
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3. Connect the Low output of Channel One to the power amplifier
powering the low frequency cabinets (left).
4. Connect the High output of Channel One to the power amplifier
powering the high frequency cabinets (left).
5. Repeat for the right side of the system (Channel Two).
6. Connect the Subwoofer output to the subwoofer amplifier.
7. Set the crossover frequency for both channels (they should be the
same if your PA cabinets are the same).
8. Set the crossover frequency for the Subwoofer output to that
recommended for the Subwoofer.
9. With the power amplifier volume controls turned all the way down,
turn on all equipment in the system.
10. With a program source running through the system, turn up the
power amplifier volume controls and slowly turn up the crossover
output controls while checking each individual output for sound and
performance.
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WARRANTY INFORMATION
Limited Warranty
Applied Research and Technology will provide warranty and service for this
unit in accordance with the following warrants:
Applied Research and Technology, (A R T) warrants to the original
purchaser that this product and the components thereof will be free from
defects in workmanship and materials for a period of one
of purchase. Applied Research and Technology will, without charge, repair
or replace, at its option, defective product or component parts upon prepaid
delivery to the factory service department or authorized service center,
accompanied by proof of purchase date in the form of a valid sales receipt.
Exclusions:
This warranty does not apply in the event of misuse or abuse of the product
or as a result of unauthorized alterations or repairs. This warranty is void if
the serial number is altered, defaced, or removed.
ART reserves the right to make changes in design or make additions to or
improvements upon this product without any obligation to install the same
on products previously manufactured.
year from the date
ART shall not be liable for any consequential damages, including without
limitation damages resulting from loss of use. Some states do not allow
limitations of incidental or consequential damages, so the above limitation or
exclusion may not apply to you. This warranty gives you specific rights and
you may have other rights, which vary, from state to state.
For units purchased outside the United States, an authorized distributor of
Applied Research and Technology will provide service.
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SERVICE
The following information is provided in the unlikely event that your unit
requires service.
1) Be sure that the unit is the cause of the problem. Check to make sure the
unit has the proper power supplied, all cables are connected correctly, and
the cables themselves are in working condition.
2) If you find the unit to be at fault, write down a complete description of the
problem, including how and when the problem occurs. Please write down a
description of your complete setup before calling Customer Service.
3) Contact our Customer Service Department at (585) 436-2720 for your
Return Authorization number or questions regarding technical assistance or
repairs. Customer Service hours are 9:00 AM to 5:00 PM Eastern Time,
Monday through Friday.
4) Pack the unit in its original carton or a reasonable substitute. The packing
box is not recommended as a shipping carton. Put the packaged unit in
another box for shipping. Print the RA number clearly on the outside of the
shipping box. Print your return shipping address on the outside of the box.
5) Include with your unit: a return shipping address (we cannot ship to a
P.O. Box), a copy of your purchase receipt, a daytime phone number, and a
description of the problem.
6) Ship your unit (keep your manual!) to:
APPLIED RESEARCH AND TECHNOLOGY
215 TREMONT STREET ROCHESTER, NEW YORK 14608 ATTN: REPAIR DEPARTMENT RA# ____________________
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311 SPECIFICATIONS
Dimensions 1.75”H x 19”W x 5.5”D
Weight 4.85 lbs. (2.2 kg)
Input Connections XLR, ¼” TRS, balanced
Output Connections ¼”TS, unbalanced
Input Impedance 100K ohms
Output Impedance 220 ohms
Maximum Input Level +21dBu
Maximum Output Level +21dBu
CMRR >75dB (typical @ 1kHz)
Frequency Response 10Hz to 40kHz, +/-.5dB
Signal to Noise Ratio >95dB, Ref: 0dBu
20Hz to 20kHz, unweighted
Dynamic Range >114dB
Total Harmonic Distortion <0.01% (20Hz-20kHz,0dBu)
Crossover Filter Type Fourth-order Linkwitz-Riley,
24dB/octave, state-variable
Crossover Frequency Range 250Hz to 6kHz
Subwoofer Filter Type Two-pole Butterworth, 12dB/ octave
Subwoofer Frequency Range 50Hz to 250Hz
Power Requirements USA – 110-125V AC / 50-60hz/ 15W
Export units configured for
country of destination.
ART maintains a policy of constant product improvement. ART reserves the
right to make changes in design or make additions to or improvements upon
this product without any obligation to install same on products previously
manufactured. Therefore, specifications are subject to change without
notice.
Applied Research & Technology
215 Tremont Street Rochester, New York 14608 U.S.A.
(585) 436-2720 - Voice www.artproaudio.com
(585) 436-3942 - FAX E-mail: cserve@artproaudio.com
© 2002 Applied Research & Technology 311-5004-100
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