A dissociation between speech understanding and perceived reverberation.

Area of Science:

• Acoustics
• Psychoacoustics
• Speech Perception

Background:

• Decreasing direct-to-reverberant energy ratio (DRR) or increasing decay time typically reduces speech intelligibility.
• It is commonly assumed that perceived reverberation (reverberance) mediates this effect, increasing with physical reverberation and subsequently decreasing intelligibility.

Purpose of the Study:

• To investigate whether perceived reverberance acts as an intermediary between physical reverberation and speech intelligibility.
• To determine if reverberance and speech intelligibility can be dissociated.

Main Methods:

• Experiment 1: Magnitude estimation of reverberance for speech stimuli convolved with manipulated impulse responses.
• Experiment 2: Speech intelligibility testing using noise-masked speech convolved with impulse responses from Experiment 1.

Main Results:

• Listeners perceived less reverberance when DRR increased at both ears (Natural Room), but not when DRR increased only at the nearer ear (Hybrid).
• Speech intelligibility was high when at least one ear received non-reverberant speech, including the Hybrid condition.
• The Hybrid condition yielded high reverberance and high intelligibility simultaneously.

Conclusions:

• Perceived reverberance and speech intelligibility can be dissociated.
• A single ear receiving non-reverberant speech is sufficient for good speech intelligibility, regardless of reverberance at the other ear.