Monaural and Binaural Speech Intelligibility and the Stereophonic Effect Based upon Temporal Cues.

Three important aspects of binaural hearing, namely: directionality, the "squelching" of reverberations, and markedly increased speech intelligibility, were all mentioned in anecdotal fashion by Koenig on the basis of some observations he made with an artificial head, two microphones, and two earphones. A Y-cord arrangement, with one microphone feeding" two earphones, or the outputs from two microphones merged and fed to two diotic phones, gave none of these three effects. Two other physicists, Knudsen and Watson, had reported improved intelligibility with binaural hearing. In these three laboratory pilot studies, the improvement of the binaural over the monaural condition was said to be quite apparent; but since no data were actually published, the force of the remarks in these three abstracts has been pretty well ignored, and no exact repetition of their apparatus and conditions has been attempted.