Energy distribution in music

A knowledge of the manner in which the acoustic power encountered in music varies with respect to frequency can be a useful tool in the design of components to be used in audio reinforcement or reproduction systems. This paper deals with the amplitude of fractional-second energy peaks, without reference to the rate of their occurrence. It is these peaks which must be considered when distortion is of primary consideration; average power is useful only in predicting temperature rise (where applicable) of signal-handling components. Throughout the discussion emphasis is placed upon the difference between average and peak energy consideration. The source material from which the distribution analysis is drawn consisted of recent commercial vinyl recordings played on a carefully equalized reproducing system. Ten various types of music are classified and a distribution curve for each is drawn. The methods used in arriving at a typical curve are shown by breaking the spectrum into octaves with a band-pass filter. The distribution information mentioned above is applied to the design of a three-channel loudspeaker system as an example of use. Other possible applications are mentioned.