Prediction of Speech Intelligibility in Noise
J. M. Pickett, Karl D. Kryter · The Journal of the Acoustical Society of America · 1954
PB word and sentence intelligibility tests were presented over earphones and loudspeakers to a crew of five listeners. Tests were conducted in four noises of different spectra. The results were compared with scores predicted by five current methods proposed for this purpose. The method of French and Steinberg, employing twenty articulation bands, predicted test results obtained in “flat” noise but failed to give satisfactory results for the other noise spectra; the shorter methods which employ a few octave bands underestimated the speech levels required to obtain specified test scores by 1 to 24 decibels. In general, the results obtained with speech presented over a loudspeaker in an anechoic room were closer to predicted values than were the results from the tests using earphones. It is concluded that existing methods of predicting speech intelligibility are not suitable for use with noise spectra deviating significantly from “flat.” Required speech levels (RSL) for satisfactory speech communication in noises of various spectra are proposed.