Release from masking in simulated reverberant environments

Abstract

It is well documented that older listeners have more difficulty in understanding speech in complex listening environments. In two separate experiments, speech intelligibility enhancement due to prior exposure to listening environment and spatial release from masking (SRM) for small spatial separations were measured in simulated reverberant listening environments. Release from masking was measured by comparing threshold target-to-masker ratios (TMR) obtained with a speech target presented directly ahead of the listener and two speech maskers presented from the same location or in symmetrically displaced spatial configurations in an anechoic chamber. The results indicated that older listeners required much higher TMR at threshold and obtained decreased benefit from prior exposure to listening environments compared to younger listeners. For the small separation experiment, speech stimuli were presented over headphones and virtual acoustic techniques were used to simulate very small spatial separations (approx. 2 degrees) between target and maskers. Results reveal, for the first time, the minimum separation required between target and masker to achieve release from speech-on-speech masking in anechoic and reverberant conditions. The advantages of including small separations for understanding the functions relating spatial separation to release from masking will be discussed, as well as the value of including older listeners. [Work supported by NIH R01 DC011828.]