Intelligibility of 1/3-octave speech: greater contribution of frequencies outside than inside the nominal passband.
We reported previously that "everyday" sentences were highly intelligible when limited to a 1/3-octave passband centered at 1,500 Hz and having transition-band slopes of approximately 100 dB/octave. The present study determined the relative contributions to intelligibility made by the passband (PB) and the transition bands (TBs) by partitioning the same bandpass sentences using 2,000-order FIR filtering. Intelligibility scores were: PB with both TBs, 92%; deletion of both TBs (leaving only the 1/3-octave PB with nearly vertical slopes), 24%; deletion of the PB (leaving both TBs separated by a 1/3-octave gap), 83%. These and other results indicate a remarkable ability to compensate for severe spectral tilt and the consequent importance of considering frequencies outside the nominal passband in interpreting studies using filtered speech.
Warren
R M
RM
Department of Psychology, University of Wisconsin-Milwaukee 53201-0413, USA. rmwarren@csd.uwm.edu
Bashford
J A
JA
D006801:Humans; D013060:Speech / Q000502:physiology*; D013067:Speech Perception / Q000502:physiology*