Audio Application Notes

Building an Audio MicroScope™

by Benchmark Media Systems February 02, 1997 3 min read

By Allen H. Burdick

Two inexpensive jack-mounted products from Benchmark Media Systems can be assembled into a very powerful test set we call The Audio MicroScope™. The Audio MicroScope™ is a tool to be used in setting up analog audio systems. Because of its extremely high gain capability, over 85 dB, it is particularly useful in hunting down signal interface problems, such as hum and buzz from RF interference, magnetic induction, and ground loops.

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Building the L-R Null Test Set

by Benchmark Media Systems February 01, 1997 4 min read

By Allen H. Burdick

In the process of broadcast matrix encoding and decoding, balancing amplitudes between the two channels of a stereo audio path is very necessary. It is necessary for the maintenance of proper headroom, dynamic range and, of course, separation.

From time to time, repair and maintenance must be performed on equipment. Returning the entire chain to a balanced condition when placing the equipment back in service, is very desirable. Most broadcast engineers have balanced a chain at the stereo generator using the L-R method. But why not balance the output of each piece of equipment throughout the studio and eliminate the trip to the transmitter? It could mean eliminating late nights, and for those who don't go off the air, it may be the only option.

While recording studios do not face the same problems as the broadcaster, much of what is recorded in a studio is broadcast. This technique, therefore, is also applicable to the maintenance of a final stereo path in a recording facility.

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Using the HPA-1 as a Long-Lines Driver

by Benchmark Media Systems January 15, 1997 4 min read

By Allen H. Burdick


The high current output configuration of the HPA-1 is ideal for use as a transformerless long lines driver. Conversion of the unit for this purpose, source, transmission line, and termination considerations will be discussed.

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Metering 70 Volt Lines

by Benchmark Media Systems January 13, 1997 1 min read

By Allen H. Burdick

A 70 Volt Meter Attenuator for Sound Reinforcement

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.

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Mix-Minus Applications

by Benchmark Media Systems January 01, 1997 2 min read

By Allen H. Burdick

Radio talk shows are currently enjoying unprecedented success. If your station has plans to add a talkshow, you will face the problem of creating a mix-minus, a signal that returns all of the program audio, except the caller's own voice, to the caller. Otherwise, echo, caused by Telco system signal delays, can confuse the caller.

If you have a production console with...

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When is a DA not a DA?

by Benchmark Media Systems January 01, 1997 3 min read

The Role of an Audio Distribution Amplifier in Professional Audio Systems

Let's face it, an Audio Distribution Amplifier (DA) is not absolutely necessary for the distribution of audio! You can daisy chain your audio from input to input these days, generally with minimal loading on the source. However, what happens if a piece of equipment on the chain fails, or someone inadvertently cuts the audio pair, or you wish to remove a piece of equipment while on the air? Well, of course, that's why we install DAs in the first place. The DA is an insurance policy. But like any insurance policy, you'd better be sure of your coverage before you need to make a claim. To examine our insurance coverage, let's review the basic criteria for good audio transmission.

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Aspects of Sampling, Oversampling, Quantisation, Dither and Noise-Shaping, as Applied to Digital Audio

by Benchmark Media Systems November 30, 1994 1 min read

By Christopher Hicks

"The aim of this article is to dispel as many of the myths surrounding the conversion of audio signals to the digital domain, and back to the analogue domain, as possible, without the aid of mathematics and (much more difficult) without the aid of diagrams."

Download the paper

Copyright, Christopher Hicks, November 1994. V1.11

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Voltage Transmission for Audio Systems

by Benchmark Media Systems January 01, 1980 1 min read

By Richard L. Hess, Audio-Video Systems Engineer, American Broadcasting Company, New York City

"The benefits of using a voltage audio transmission system in broadcast facilities is investigated. State of the art microphone preamplifier requirements and an ideal voltage system distribution amplifier are outlined. The application of the Peak Program Meter to the new systems and the modified installation at WABC-TV are covered."

 

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