ALM 473


Dual Mono/Stereo Audio Level Master

The ALM473 Dual Audio Level Master stabilizes audio volume level by adjusting gain so that the output remains constant when the input level varies wildly. The ALM473 will correct audio level changes over a range of more than 30dB.

It has two completely independent control systems so that it can operate as two separate mono audio level controllers. A jumper on the PC Card enables the Audio Level Master to operate in the stereo mode, or as two independent monaural Audio Level Masters.

Each ALM473 card can handle one stereo L/R channel or two monaural audio channels. A program dependent level control system prevents “ducking” of background sound when doors slam or guns go off, and also prevents background sound from becoming louder when foreground speech stops.

The Multi-band control system prevents “pumping” in the audio to prevent audio artifacts from being created. This allows the audio Level Master to control the audio levels without adding a sound of its own. The professional noise gates freeze the audio level when the audio subsides to prevent the “Inrush” of noise when the program is quiet.

A dual L.E.D. display indicates the degree of gain control being exerted on each channel. A separate L.E.D. displays the High Frequency limiting for each channel. An L.E.D. display shows the status of each gate. Each of the two channels will control audio input variations over a 32 dB range while holding the output level within 0.5 dB.

The output level is field programmable by jumpers on the PC Card. The output level can be set for a balanced -4, 0, +4 dBm and also -10 dBm unbalanced.

The Audio Level Master is a broadcast quality, full professional grade, automatic audio level control system, built with the price and quality conscious audio professional in mind.

Each ALM473 card contains one full stereo or two mono channels, and nine cards will fit into one RMS-400 mainframe. The RMS-400 mainframe will hold audio level control for up to 18 monaural channels or 9 stereo channels in just 3 “RU” rack unit spaces. The ALM473 can be used for mono channels and then easily converted to stereo in the field with no re-calibration.


Input Level -20 to +10 dBm (adj. range)

Clip Point+26 dBu Input Level
Input Level Control Adjustable Front Panel Control
Impedance Balanced Hi-ZCommon Mode Suppression 40 dB Minimum
Mode Dual Mono or Stereo
Connector Snap-In Screw Terminal




Frequency Response 20 Hz to 20 KHz, 0.1 dB TYP.
Control Range 32 dB
Gate Gain freeze on Low Level
Distortion 0.05 %THD TYP.
Signal-To-Noise80 dB Minimum




Level (Programmable)-4, 0, +4 dBm, -10 dBm (unbal)
ImpedanceLow-Z (Drives 600 Ohms)

Connector Snap-In Screw Terminal


Level Control Dual Multicolor L.E.D. Gates Green L.E.D. Indicators
High Frequency Limiting Amber L.E.D.


Card Fits in one of nine spaces in
the RMS-400 Mainframe

Power Requirement +/-12 VDC, 150 mA (RMS-400)

For more information and pricing call: 800-235-6960.

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