The visual component of speech reception in conference centers

SPEECH INTELLIGIBILITY STUDIES WITH UNIVERSITY STUDENTS IN A 20 FT BY 45 FT LONG LECTURE HALL CONFIRM THE STRIKING EFFECT OF SPEECH-TO--NOISE RATIO ON INTELLIGIBILITY. THE CONTRIBUTION OF VISUAL CUES TO SPEECH INTELLIGIBILITY IS ALSO SHOWN TO BE VERY CONSIDERABLE, ESPECIALLY WHEN THE LEVEL OF AUDIBLE SPEECH AT THE RECEIVER IS NEAR THE BACKGROUND NOISE LEVEL. THE AMOUNT OF IMPROVEMENT IN SPEECH INTELLIGIBILITY IS SHOWN TO DEPEND UPON THE ILLUMINATION LEVEL ON THE SPEAKER AND THE DISTANCE FROM THE SPEAKER.