Reverberant overlap- and self-masking in consonant identification

Area of Science:

• Acoustic Phonetics
• Psychoacoustics
• Speech Perception

Background:

• Reverberation degrades speech intelligibility by altering acoustic signals.
• Two primary effects of reverberation are overlap-masking and self-masking.
• Understanding these effects is crucial for speech processing in adverse acoustic conditions.

Purpose of the Study:

• To investigate the distinct effects of overlap-masking and self-masking caused by reverberation on consonant identification.
• To compare the impact of reverberation with other masking conditions like babble and shaped noise.
• To analyze the contribution of overlap-masking and self-masking to overall consonant identification errors in reverberant environments.

Main Methods:

• Ten normal-hearing subjects participated in the study.
• Eight consonants (/p, t, k, f, m, n, l, w/) were used as stimuli.
• Consonant identification was tested in quiet, babble noise, shaped noise, and room reverberation conditions, using both natural and synthesized speech.

Main Results:

• Reverberation's effect on consonant identification following /s/ differed from masking by /s/-shaped noise or babble.
• For synthetic syllables, errors in reverberation were approximated by the sum of errors from overlap-masking (via /s/-shaped noise) and self-masking (via reverberation).
• Self-masking within consonants was identified as a significant contributor to errors in reverberant conditions.

Conclusions:

• Reverberation introduces distinct masking effects that impact consonant perception.
• Self-masking within consonants plays a critical role in speech intelligibility degradation due to reverberation.
• The findings provide insights into the acoustic mechanisms underlying speech perception challenges in reverberant spaces.