[Study of low frequency release time in WDRC on hearing-impaired individual in mandarin language environment].

Objective: To investigate the influence of low frequency release time of WDRC(wide dynamic range compression)to speech recognition score (SRS) of deaf subjects with hearing aids in mandarin language environment. Method: Release time constants are set differently from the values of 50 ms,100 ms,200 ms,400 ms and 800 ms in low frequency (LF) channel,with 3 kinds of shaped noise,combining a certain LF release time constant with a certain shaped noise forms 15 different groups of experimental conditions. The testing material is mandarin sentences which are the outputs of simulation in the 15 different release time combinations. Result: If the release time is set the value of 400 ms,the patients with hearing aids can get the best mandarin speech intelligibility; the type of babble noise have significant effects on mandarin SRS. Conclusion: Statistical analysis of test results shows that the release time in LF channel or the type of shaped noise trends to influence mandarin SRS.