| Abstrakt: |
Psychoacoustic MTFs were measured by embedding a probe tone in SAM speech noise. The speech noise was 70 dB SPL overall, and the modulation depth of this noise was 60 dB. The modulation frequencies were: 0, 2.5, 5, 10, 20, and 35 Hz. The duration of each tone pip was 4.7 ms for frequencies 500, 1414, and 4000 Hz. Bandwidths (3 dB) at each of the frequencies were 19, 22, and 18 Hz. Skirt slopes were between 6 and 7 dB/octave. Simple masking nearly predicted changes in these MTFs in noise. A Speech Transmission Index (STI) derived from the MTFs in noise was no better correlated (r = 0.95) with speech recognition scores than was the STI calculated according to H. J. M. Steeneken and T. Houtgast, J. Acoust. Soc. Am. 67, 318-326 (1980). [Work supported by the Veteran's Administration.] [ABSTRACT FROM AUTHOR] |
