Audio Class: The Basics

Signal, Noise & Distortion

Signal is the sound we want

Noise is other, unwanted, sounds riding along with the signal

• One common type of noise is 60 Hz hum from power line
• Another common noise is hiss (white noise) from electronics or from the wind

Noise is frequently expressed as a "Signal-to-noise Ratio" in dB. 60 dB or greater is desirable.

Distortion is an unwanted modification of the signal

• A common type of distortion is clipping (like fuzz guitar)

Distortion is measured as a percentage of the desired signal. Less than one tenth of one percent ( 0.1%) is desirable.

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Audio Class © 1993 Richard Crowley