Audible Frequency Ranges of Music, Speech and Noise

NY sound transmission system, if it is to give faithful reproduction, should transmit all the audible frequencies of a sound in their proper relative intensities. To give acceptable reproduction, it should transmit those frequencies considered most necessary for any particular application. The audible frequency range depends upon physical factors--the frequency-amplitude characteristics of a sound and the hearing characteristics of the average ear--whereas the acceptable frequency range must be determined by judgment when engineering or economic considerations limit transmission. As engineering limitations disappear and practical design becomes more a matter of economics a knowledge of both audible and acceptable limits increases in importance. The program of listening tests described in this paper was undertaken primarily to establish the audible frequency ranges of the sounds most often encountered in sound reproduction, but some tests bearing on acceptable ranges were included. The sounds were transmitted through an electro-acoustic system equipped with electrical filters by means of which all frequencies above or below any desired cut-off could be suppressed, and observers determined the high and low frequency cut-offs causing just perceptible differences in the transmission. All * Presented at the Camden mtg. of the Acous. Soc. Amer., May 4-5, 1931. lished in the Jour. Acous. Soc. Amer., July, 1931. 616 Pub- AUDIBLE FREQUENCY RANGES 617 audible frequencies of the sounds were included in the range between the cut-offs thus delineated.