Intelligibilities of 1-octave rectangular bands spanning the speech spectrum when heard separately and paired

Abstract

There is a need, both for speech theory and for many practical applications, to know the intelligibilities of individual passbands that span the speech spectrum when they are heard singly and in combination. While indirect procedures have been employed for estimating passband intelligibilities (e.g., the Speech Intelligibility Index), direct measurements have been blocked by the confounding contributions from transition band slopes that accompany filtering. A recent study has reported that slopes of several thousand dBA/octave produced by high-order finite impulse response filtering were required to produce the effectively rectangular bands necessary to eliminate appreciable contributions from transition bands [Warren et al., J. Acoust. Soc. Am. 115, 1292-1295 (2004)]. Using such essentially vertical slopes, the present study employed sentences, and reports the intelligibilities of their six 1-octave contiguous passbands having center frequencies from 0.25 to 8 kHz when heard alone, and for each of their 15 possible pairings.

Critical bandwidth speech: Arrays of subcritical band speech maintain near-ceiling intelligibility at high amplitudes

“…One study employed sentences (Warren et al, 2005) and the other employed word lists (Warren et al, 2011). The intelligibilities of these 1-octave pairings in each study were hyperadditive whether the two octave bands were contiguous or separated by 2, 3, or 4 octaves.…”

“…Two studies determined the intelligibility of the six 1-octave RBs, spanning the speech spectrum from 0.25 to 8 kHz, that were measured both singly and for all 15 possible pairings (Warren et al, 2005(Warren et al, , 2011. One study employed sentences (Warren et al, 2005) and the other employed word lists (Warren et al, 2011).…”

A review of the perceptual effects of hearing loss for frequencies above 3 kHz

“…The SII does not explicitly take into account the fact that the information in speech (for example the envelope fluctuations) is correlated across frequency bands: the closer the centre frequencies of the bands, the higher is the correlation (Crouzet & Ainsworth, 2001). Hence the SII does not give accurate predictions of intelligibility for speech that is filtered into very narrow frequency bands whose separation is varied (Warren et al, 2005). Also, the SII does not give accurate predictions of intelligibility for speech in fluctuating background sounds (Rhebergen & Versfeld, 2005).…”

Effects of linguistic experience on the ability to benefit from temporal and spectral masker modulation

“…Oxenham and Simonson hypothesized that this decrease in benefit was due to reduced redundancy within the target speech signal. Natural speech is highly redundant, a feature that normal-hearing listeners are able to exploit when provided with temporally or spectrally degraded signals (Warren et al, 1995;Warren et al, 2005;Wang and Humes, 2010). Reducing that redundancy, by virtue of filtering the target, could reduce the quality of glimpses available in the masker modulation minima.…”