Predicted intelligibility was estimated from the transfer function relating SII to intelligibility scores determined in preliminary experiments. For conditions in which the SII was equated and predicted intelligibility was maximized, intelligibility ratings remained essentially the same across conditions while clarity changed modestly. For conditions in which predicted intelligibility decreased, both clarity and intelligibility ratings decreased in a similar manner. Although high correlations were observed between clarity and intelligibility ratings, intelligibility ratings were consistently higher than clarity ratings for comparable conditions. The results suggest that normal-hearing listeners produce clarity ratings or intelligibility ratings for the same speech material and experimental conditions that are highly related but may differ in magnitude.
Caution is required when substituting clarity for intelligibility.