Twenty listeners rated 10 speakers from the Air Force Cambridge Research Laboratory’s (AFCRL) speaker library, using a 12-item rating form developed from Osgood’s (1957) semantic differential rating form techniques. Physical characteristics of the same speakers' voices also were measured. The results revealed that speakers can be reliably differentiated on the basis of (1) listener judgments alone, (2) listener judgments combined with physical voice measures, and (3) physical voice measures alone. Speakers' voice characteristics, as determined by listeners' judgments alone, can be accounted for by two basic factors which account for over 90% of the variance. Factor analysis of both judged and actual physical voice measures led to a 5-factor solution accounting for more than 90% of the total variance.