Speaker recognizability testing for voice coders

Users of low data rate voice coders now demand good speaker recognition in addition to quality and intelligibility. Speaker recognizability was one of the selection criteria for the DoD Digital Voice Processor Consortium in selecting a new standard 2400 bps algorithm. We have developed a speaker recognition test based on same-different judgments for pairs of sentences spoken by 10 male and 10 female speakers. Preliminary experiments showed that the sensitivity of the test is similar to that of currently used acceptability and intelligibility tests. Male and female talkers produced somewhat different rank orderings, but averaging over males/females gave results that "make sense" when compared with intelligibility and acceptability scores for the same coders. The results of these experiments determined the speaker recognition test procedures that were used in the 2400 bps coder final selection process.