Audio international EN-B40MT Series Original operating instructions

7300 Industry Drive, North Little Rock, AR 72117
Phone: [phone] Fax: [phone]
Product Guide to
Installation & Operation
Mid-Bass Speaker Enclosure
Model #:
EN-B40MT-xx & EN-B41MT-xx
Document # 540015

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Document #540015, Rev. A, Model No.: EN-B40MT-x & EN-B41MT-x
Revision History
Rev. Level Date Description
IR 11/97 Initial Release
A 1/98 Updated Drawing
Applicable Documents
Document
# Drawing # Description Rev. #
N/A 521608 EN-B40MT-xx Drawing A
N/A 521609 EN-B40MT-xx Drawing A

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Document #540015, Rev. A, Model No.: EN-B40MT-x & EN-B41MT-x
Service Bulletin List
Service
Bulletin # Subject Manual
Revision
#
Manual
Revision
Date
List of Illustrations
Section
No. Description Page #

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Document #540015, Rev. A, Model No.: EN-B40MT-x & EN-B41MT-x
Table of Contents
Section Description Page
1.0
General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2 Purpose of the Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3 Operational Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4 Optional Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.0
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1 Prior to Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2 Unpacking and Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.3 Cautions & Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.4 Wiring Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.5 Physical Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.6 Electrical Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.7 Pinouts / Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.8 Connector / Mating Connector Information . . . . . . . . . . . . . . . . . . . . . . . 7
2.9 Post-Installation Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.0
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.1 Audio Input. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.2 Audio Adjustments .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.0
Troubleshooting Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.0
Specification and Drawings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.1 Unit Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.2 Applicable Drawings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9

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Document #540015, Rev. A, Model No.: EN-B40MT-x & EN-B41MT-x
MODEL NO’s
EN-B40MT-xx & EN-B41MT-xx
Mid-Bass Speaker Enclosure
1.0 General Information
1.1 Introduction
This manual contains information for the installation and operation of the Audio
International, Inc. (AI) Mid-Bass Speaker Enclosure, Model No’s:
EN-B40MT-xx & EN-B41MT-xx. Information contained within this publication
includes relative physical, mechanical, and electrical characteristics. Also
included within this publication are additional references needed for installation
and operation of the unit.
The EN-B40MT-xx and EN-B41MT-xx are high quality, 5” coaxial speakers
consisting of a mylar tweeter and 5” mid-bass driver. The “xx” in the product
model number indicates speaker resistance and type of connector. This
component is built to rugged aircraft standards and is easily incorporated into new
or existing systems. Features include a 5-year warranty, 10-year proven design
reliability, black anodized finish, lightweight construction, integral mounting
hardware, and the latest in speaker technology.
1.2 Purpose of the Equipment
The EN-B40MT and EN-B41Mt are full range speaker enclosures in left and right
hand versions. These enclosures have solid welded seams and acoustic damping
for clean sound with no “buzz” or vibration. Specialized acoustic engineering
packs maximum performance into the most compact enclosures possible. This
enclosure is capable of 40 watts RMS input.
1.3 Optional Equipment
Audio International, Inc. offers a comprehensive family of Cabin Ready
Enclosures. For limited space applications, AI offers combination enclosures
with excellent full range sound. For more elaborate systems, better sound can be
obtained using combinations of low range woofers/subwoofers and high range
mid/tweet or full range enclosures. Custom speaker enclosures are available on
request. Contact your AI representative for more information.

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Document #540015, Rev. A, Model No.: EN-B40MT-x & EN-B41MT-x
2.0 Installation
2.1 Prior to Installation
Proper wire size for the power and ground connections should be chosen giving
consideration to the current carried and the length of the wire run. The En-
B40MT-xx and EN-B41MT-xx must be attached to conform to the standards
designated by the customer, installing agency, and existing conditions as to the
unit location and type of installation. The following should be carefully
considered before installing:
2.1.1 Select a mounting location for the unit. Mounting screws are required to
secure the unit (10-32 SKB blind riveting nuts). Refer to Section 5.0,
Specifications and Drawings, for mounting hole diameters and
configuration.
2.2 Unpacking and Inspection
2.2.1 Carefully open the packaging and remove the speaker enclosure. Inspect
the unit(s) for damage. Retain the packing materials and packing list.
Verify that all components have been included in the package per the
packing list. The components should arrive in good condition. However,
occasionally damage does occur in shipping.
If damage has occurred, a claim must be filed with AI within 24 hours
after unpacking and a “Return Request Authorization Number”must be
obtained from AI. Refer to the front cover of this manual for address and
telephone number of the Audio International, Inc. authorized dealership.
Repackage the unit in its original packaging materials and return it to AI
following instructions given. If no return is necessary, retain the packing
materials for storage or reshipment if necessary.
2.3 Cautions & Warnings
2.3.1 All connections to the EN-B40MT-xx and EN-B41MT-xx should be
shielded, twisted pair and properly grounded.
2.3.2 DO NOT connect or disconnect the enclosure while power is applied.
2.3.3 DO NOT remove any factory-installed screws. Damage to the units may
result and void any warranties.

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Document #540015, Rev. A, Model No.: EN-B40MT-x & EN-B41MT-x
2.4 Wiring Requirements
2.4.1 The installing agency must supply and fabricate all external cables. The
length and routing of external cables must be carefully studied and
planned before attempting installation of the equipment. Allow adequate
space for installation of cable and connectors. Avoid sharp bends and
placing cables near aircraft control cables. Maintain a minimum clearance
of three (3) inches from any control cable. If wiring is run parallel to
combustible fluid or oxygen lines, maintain a separation of six (6) inches
between the lines.
2.4.2 All signal wires must be 20 AWG minimum, 16-18 AWG preferred. All
audio lines require twisted, shielded cable with the cable shields grounded
at the source. All wires must be in accordance with MIL-W-22759 or
equivalent. Twisted, shielded cable must be in accordance with MIL-W-
27500 or equivalent.
2.5 Physical Requirements
2.5.1 Do not restrict airflow in front of the enclosure. Airflow should be a
minimum of 70% unrestricted. Heavy fabrics and solid objects can
restrict airflow and damage speaker.
2.5.2 Refer to section 2.7 for pinout and description. Do not drill any additional
holes in the enclosure as it functions as an airtight unit.
2.5.3 Do not remove the speaker from the enclosure; the speaker is sealed in
place to provide optimum performance.
2.5.4 Refer to Section 5.0 for unit dimensions and attachment points.
2.6 Electrical Connections
2.6.1 Refer to Section 5.0 for electrical specifications.
2.7 Pinouts / Descriptions
EN-B40MT-xx and EN-B41MT-xx pins and descriptions are as follows:
Pin
No. Description
1 Audio Input Positive
2 Audio Input Negative
2.8 Connector / Mating Connector Information
2.8.1 The enclosure utilizes one of two connectors; a two pin molex or milspec
cannon connector.

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Document #540015, Rev. A, Model No.: EN-B40MT-x & EN-B41MT-x
2.9 Post Installation Test
2.9.1 Verify all connections to the unit(s).
3.0 Operations
3.1 The EN-B40MT-xx and EN-B41MT-xx contains two independent speakers. A
mylar tweeter and a 5”mid-bass speaker are mounted as a single unit. This unit
also contains the crossover network that separates high range (above 135 kHz)
and low range (below 135 kHz) audio input.
The enclosure utilizes a sealed aluminum housing packed with denser than air
material to achieve optimal performance for the speakers.
4.0 Troubleshooting Guide
Should difficulties arise with the enclosure(s), verify all connectors are making contact to
the unit. Contact Audio International, Inc. for guidance if difficulties persist.
5.0 Specifications and Drawings
5.1 En-B40MT-xx and EN-B41Mt-xx Unit Specifications
Physical Specifications
Housing Lightweight Aluminum
Dimensions Length-10.6”, width-5.1”, height-5.8”
Weight 3.65 lbs. / 1.66 kg.
Electrical Specifications
Power Handling 40 watts RMS
Audio Impedance 4 or 8 ohms
Frequency Response 95 Hz to 19 kHz (+/- 4dB)
Total Harmonic Distortion < 1% at 5 watts per channel

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Document #540015, Rev. A, Model No.: EN-B40MT-x & EN-B41MT-x
5.2 Applicable Drawings:
5.2.1 An illustration of the speaker enclosure is as follows: