Effects of reverberation on perceptual segregation of competing voices

Abstract

Two experiments investigated the effect of reverberation on listeners' ability to perceptually segregate two competing voices. Culling et al. [Speech Commun. 14, 71-96 (1994)] found that for competing synthetic vowels, masked identification thresholds were increased by reverberation only when combined with modulation of fundamental frequency (F0). The present investigation extended this finding to running speech. Speech reception thresholds (SRTs) were measured for a male voice against a single interfering female voice within a virtual room with controlled reverberation. The two voices were either (1) co-located in virtual space at 0 degrees azimuth or (2) separately located at +/-60 degrees azimuth. In experiment 1, target and interfering voices were either normally intonated or resynthesized with a fixed F0. In anechoic conditions, SRTs were lower for normally intonated and for spatially separated sources, while, in reverberant conditions, the SRTs were all the same. In experiment 2, additional conditions employed inverted F0 contours. Inverted F0 contours yielded higher SRTs in all conditions, regardless of reverberation. The results suggest that reverberation can seriously impair listeners' ability to exploit differences in F0 and spatial location between competing voices. The levels of reverberation employed had no effect on speech intelligibility in quiet.

Effects of source-to-listener distance and masking on perception of cochlear implant processed speech in reverberant rooms

“…Reverberant sound energy typically creates a temporal "smearing" of speech that imposes overlap masking on contiguous phonemes, lengthens the durations of words, and fills quiet and/or low-intensity speech segments with unwanted sound ͑Bolt and MacDonald, 1949; Houtgast and Steeneken, 1985;Nabelek et al, 1989;Dreschler and Leeuw, 1990;Helfer, 1994;Culling et al, 2003͒. As a result, intelligibility decreases in conjunction with the reductions in speech envelope modulation depth imposed by temporal smearing ͑Houtgast and Steeneken, 1985͒.…”

Physiology, Psychoacoustics and Cognition in Normal and Impaired Hearing

“…However, noise and reverberation can both degrade speech intelligibility under realistic "cocktail-party" listening conditions (Nabelek 1993;Culling et al 1994Culling et al , 2003. Neurophysiological studies of concurrent-sound segregation have concentrated on harmonic complex sounds, with a fundamental-frequency difference (ΔF0), heard under idealized (quiet, anechoic) conditions (e.g., Palmer 1990; Keilson et al 1997;.…”

A Supervised Learning Approach to Monaural Segregation of Reverberant Speech

“…In other words, segregation in highly reverberant conditions is probably a harder task than in low reverberant conditions. Subjective tests reveal that human listeners' ability to separate competing voices degrades with increasing levels of reverberation [17].…”