Speech intelligibility and talker gender classification with noise-vocoded and tone-vocoded speech

Vocoded speech provides less spectral information than natural, unprocessed speech, negatively affecting listener performance on speech intelligibility and talker gender classification tasks. In this study, young normal-hearing participants listened to noise-vocoded and tone-vocoded (i.e., sinewave-vocoded) sentences containing 1, 2, 4, 8, 16, or 32 channels, as well as non-vocoded sentences, and reported the words heard as well as the gender of the talker. Overall, performance was significantly better with tone-vocoded than noise-vocoded speech for both tasks. Within the talker gender classification task, biases in performance were observed for lower numbers of channels, especially when using the noise carrier.