Metering 70 Volt Lines

A 70 Volt Meter Attenuator for Sound Reinforcement

By Allen H. Burdick


It is often desirable to monitor the levels on distributed audio PA speaker lines, known as 70 volt lines. It's simple with the right tools. This app-note shows how.

Many times a sound reinforcement system that uses the industry accepted 70 volt interface system needs to be metered. Benchmark SPM-220 and SPM-320 meter systems as well as the RPM-1, VU-1 combination can easily do the job and allow the operator to see the audio levels both in VU (average) levels as well as in PPM (peak) mode.  In other words by using the peak metering capability of the Benchmark meter systems, an operator can, at any place on the system, not just the amplifier room, see whether or not his amplifier hit clip.

The following is an attenuator that will do the trick.

Fig. 1.0 Meter System Attenuator

Benchmark Media Systems
Benchmark Media Systems