Consonant recognition in noise with temporal cues: I. Effects of temporal envelope enhancement on identification performance

Abstract

This study sought to determine whether consonant identification performance in noise can be improved by applying an expansive nonlinearity to the temporal envelope of the speech stimuli. Consonants in /a-consonant-a/ context were processed through four broad bandpass filters, half-wave rectified and lowpass filtered at 500 Hz to extract the temporal envelope from each band. The envelope from each band was used to modulate a band-limited noise. In each band, the temporal envelope was either left intact or expanded by raising it to the power 1.414 or 2. Three signal-to-noise ratios (S/N) were used: −6, 0, and +6 dB. Twelve young normal-hearing listeners were tested twice in each condition, one week apart, using a forced-choice paradigm. Overall, identification performance increased with S/N and training. For each S/N and testing session, small but consistent improvements in identification performance of 2%–6% were observed when raising the envelopes to the power 1.414 or 2. Information transmission analysis performed on the aggregate confusion matrix showed that improved identification with expanded envelopes was mainly due to an increase in the reception of voicing.