Audio Technica SmartMixer AT-MX341a Installation And Operation Manual

AT-MX341a SmartMixer

®

Four-channel Automatic Microphone Mixer

Installation and Operation

Contents

Introduction .......................................................................................................................3

What is the SmartMixer®? ........................................................................................................3

Features .....................................................................................................................................3

Front Panel ................................................................................................................................4

Rear Panel .................................................................................................................................5

Installation and Setup ................................................................................................6

Priority Microphones and Lockout Bus .................................................................................6

Preamplifier Gain .....................................................................................................................7

Output Gain ..............................................................................................................................7

Phantom Power ........................................................................................................................7

Output Level LED Meter ..........................................................................................................8

Adjusting “Off” Attenuation ...................................................................................................8

Control Voltage Out .................................................................................................................9

Daisy-chaining Mixers ...........................................................................................................10

Rack Mounting ........................................................................................................................10

Security Caps ..........................................................................................................................10

Specifications .................................................................................................................11

Warranty .............................................................................................................................12

2

Introduction

Please Note!

This manual assumes use of microphone-level inputs and line-level output, the most typical
SmartMixer application. However, all inputs and the output may be individually switched
internally to achieve any combination of mic- and line-level input/output. See page 7 for details.

What is the SmartMixer?

The AT-MX341a SmartMixer®Automatic Microphone Mixer is a microprocessor controlled,
automatic switching, four-channel microphone mixer.

The microphone inputs are XLRF-type balanced, with 12-volt phantom power available on
pins 2 and 3. The output is XLRM-type balanced, non-inverting.

AT-MX341a mixers can be daisy-chained via the included AT8325/1.0 Link Cable and special
connectors on the rear panel. The control bus and the audio are carried between mixers by the
link cable. The result is that all microphones on a multi-mixer system can be controlled by one
microphone connected to any mixer. Since all of the mixers are independently powered, there
is no practical limit to the number of SmartMixers that can be daisy-chained.

Features

To custom-tailor conferencing needs, the mode of each microphone channel can be indepen­dently switched via the front panel “priority pre-select” DIP switches. The combination of
switch settings results in three different modes of priority selection/operation.

In any of the three modes of automatic operation, when everyone stops talking, the last
microphone “on” will remain “on.” In a teleconferencing, recording, or broadcast application,
this feature will provide continuous room ambience. This feature is cascaded throughout all
linked mixers so that only one microphone in the entire system will remain on.

Each input channel has an independent gain control on the front panel. Substantial gain
reserve and adjustment range permits microphones of widely differing sensitivities to be used
together successfully.

When a microphone is “off,” its input is only attenuated. This attenuation is factory set at
8 dB. The amount of “off” attenuation can be internally adjusted between 6 dB and 20 dB if
desired. (See page 8, “Adjusting ‘Off ’ Attenuation.”)

A “manual” setting on the front panel bypasses the AT-MX341a’s automatic switching and
attenuation functions, causing the unit to behave like a conventional 4-channel mixer. In this
mode, the relative level of each microphone is strictly a function of the position of its respective
front-panel gain control.

3

AT-MX341a Front Panel

1. Power switch.

2. Power “on” indicator.

3. Input Gain controls. Adjust inputs for microphone sensitivities and/or

operating conditions.

4. Selected Channel LED indicators. Indicate which channels are “on” or “active.”

5. Output Level LED meter. Indicates RMS output level of the mixer. “Zero” (0) level is

factory calibrated for an output of +4 dBm into 600 ohms (Master Level control fully
clockwise). Can be set for peak output level indication via internal switch (see page 8).

6. Priority Pre-select switches. A switch in the “up” position assigns the respective

channel priority over the other channels. A priority channel can not be locked out by
other channels. Any combination of priority/non-priority selections is allowed.

7. Master Level control. Normal setting is fully clockwise (full output). If reducing the

mixer’s output is necessary, carefully turn the control counter-clockwise as needed with
a small screwdriver. Once set as desired, the control may be protected from unauthorized
adjustment by covering the panel hole with a sticker provided with the security caps.
(This control does not affect the meter indication.)

8. Master Threshold/Manual control. Sets the reference level that must be exceeded

for a microphone to be considered “in use.” Adjust to keep background noise level from
triggering microphones. “Manual” setting bypasses all of the SmartMixer’s automatic
functions.

9. Lockout LED indicator. Shows when lockout bus is active. Also aids in setting

Master Threshold.

Figure 1. Front panel

Gain 4Gain 3Gain 2Gain 1

Power

AUTOMATIC MICROPHONE MIXER

Selected Channel

AT-MX341a

Master

Threshold

Manual

Master

Level

Lockout

Output Level

-20 -10 -6 -3 0 +3 +6

Priority Pre-select

1

2

3

4

➋

➌

➏➍

➊

➐ ➒

➎

➑

4