Marshall Amplification AR-AM4-BG-2 User manual

Broadcast A/V Division
AR-AM4-BG-2
Multichannel Analog Audio Monitor
User Manual
[Firmware Version 0.43]

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Table of Contents
2. Package Contents
3. Front Panel Description
4. Control Button Detail
5. Rear Panel Description
6. Operation
7. Metering and Indicators
8. Software - Control App
9. Serial Connection
10. Operation
11. Updating
12. Specifications
Warranty
1. Features
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03 High Performance Audio
• Matches or exceeds many larger 2RU designs
• Enough “punch” for the noisiest server rooms
Multiple Inputs
• 4 Analog XLR Balanced – 4 Inputs x 2 Channels Each
Outputs
• 1 Analog XLR Balanced - 2 Channel
LED VU Display
• Provides active indication of audio input activity
Controllable via RS-232 Serial
• Remote control application downloadable from Marshall website
• Select sources, mute, solo, volume, etc.
Compact 1RU Design Saves Rack Space
• Minimum size
• Low power consumption, low heat into rack
• Compact size which does not compromise audio volume
• AR-AM4 Main Chassis
• 12-volt Universal Power supply (120/240V – 50/60Hz)
• Remote Control Application (free download from website)
1. Features
2. Package Contents

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1. Speakers
Provides sound from two channels except when Solo buttons are pressed
2. Headphone Jack
3. Volume Knob / Mute Button
Turn the knob to adjust the sound level out of both speakers
Press in on the knob to instantly mute the speaker
4. Headphone Jack
Designed to accept stereo headphones with 3.5mm plug
5. Input and Solo Left/Right Select Buttons
Select either channel for monitoring from both speaker
6. LED VU Meter Display
7. LED Indicator Lights
• Phase – Indicates audio in-phase / out-of-phase conditions
• Mute – Indicates when speakers have been muted
8. Balance Knob
Select either speaker or adjust balance between them
3. Front Panel Description
1. Input Select
Press one of these four buttons to monitor the corresponding input
2. Solo Left & Solo Right
Press isolate either the left or right channel only
Note: Sound will come out of both speakers when Solo is selected but will originate from a
single source.
1. Power Switch
2. 12-Volt DC Power Input – Coaxial, Center Positive
3. RS-232 Serial Control 9-pin D-Sub Port and Loop Out
4. Analog Balanced XLR +4dBu Output Pair (2 channels)
5. Four Analog Balanced XLR +4dBu Input Pairs (8 channels)
4. Control Button Detail
5. Rear Panel Description

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Controls on the AR-AM4-BG-2 are designed to be user-friendly and straight-forward. Simply press
one of the four Input buttons to select the desired source, then adjust the volume knob to the
desired listening level. Pressing in on the Volume knob will instantly mute both speakers. A red LED
next to the Balance knob will light whenever the audio is muted.
Press either Solo Left or Solo Right to hear sound from only the Left or Right channel. The selected
source will be heard from BOTH speakers.
Adjust the Balance knob to hear the sound from just one speaker or to match Left and Right sound
levels. A slight detent “bump” can be felt as the knob is rotated through the middle point to indicate
that balance is centered.
Note: The audio from the two Output connectors on the rear panel is affected only by the four input
selector buttons. Other controls such as Solo, Volume, Balance, and Mute will not affect the Output.
The front panel has two LED VU meters. They are calibrated to indicate “0” when the audio input is
+4dBu broadcast standard level.
(+4dBu is defined as a 1KHz tone at 1.23 Volts RMS or 3.47 Volts peak-to-peak across pins 2 & 3
of the input XLR connector).
6. Operation
7. Metering and Indicators
Download
A free application is available for download from the Marshall Electronics website at:
www.marshall-usa.com/
The AR-AM4-BG-2 may be operated and configured from a Windows® computer by a Serial (RS-
232) link.
Download, unzip and extract the file “AR-AM4-BG-2.exe” to a folder or to the desktop. Double-
click the file and it will open immediately and look like this:
8. Software - Control App

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To control the AR-AM-4 using an RS-232 serial link, first select the port number. The correct port
number will likely be the one with the highest numeric value.
Note: A serial connection will require either a serial port on the PC or a serial adapter device most
likely attached to the computer by USB. The most common connector type will be a 9-pin D-Sub
similar to the one on the back of the AR-DM51-B. When that is the case, a successful connection
can be made by using a straight through cable (not a “Null Modem Cable”). It is only necessary to
make the three connections shown here.
Computer AR-DM51-B
Pin 2 ---------------- Pin 2 (Tx)
Pin 3----------------- Pin 3 (Rx)
Pin 5 ---------------- Pin 5 (Ground)
9. Serial Connection 10. Operation
Once a connection has been established between the control application and the AR-AM4-BG-2,
operation is simply a matter of clicking on the desired functions.
All of the front panel functions can be operated through the control application screen with the
exception of the Balance control.
In the example below, Input 1 has been selected, the speakers are unmuted and the sound from the
Right channel is being heard from both speakers.