Methods for the Calculation and Use of the Articulation Index

Speech-intelligibility testing is an expensive and time-consuming operation that requires laboratory test conditions. In an attempt to short-cut or make unnecessary this type of testing, a procedure was developed by French and Steinberg J. Acoust. Soc. Am. 19, 90–119 (1949) for calculating from physical and acoustical measurements made on a communication system a measure that is indicative of the intelligibility scores that would be obtained for that system under actual test conditions. This measure is called the “Articulation Index” (AI). Methods of calculating AI have been improved and elaborated to the point where several methods for its calculation, herein reported, can be proposed for use in the evaluation of most speech communication systems.