Effects of noise on speech production: Acoustic and perceptual analyses

Abstract

Acoustical analyses were carried out on a set of utterances produced by two male speakers talking in quiet and in 80, 90, and 100 dB SPL of masking noise. In addition to replicating previous studies demonstrating increases in amplitude, duration, and vocal pitch while talking in noise, these analyses also found reliable differences in the formant frequencies and short-term spectra of vowels. Perceptual experiments were also conducted to assess the intelligibility of utterances produced in quiet and in noise when they were presented at equal S/N ratios for identification. In each experiment, utterances originally produced in noise were found to be more intelligible than utterances produced in the quiet. The results of the acoustic analyses showed clear and consistent differences in the acoustic-phonetic characteristics of speech produced in quiet versus noisy environments. Moreover, these acoustic differences produced reliable effects on intelligibility. The findings are discussed in terms of: (1) the nature of the acoustic changes that take place when speakers produce speech under adverse conditions such as noise, psychological stress, or high cognitive load; (2) the role of training and feedback in controlling and modifying a talker's speech to improve performance of current speech recognizers; and (3) the development of robust algorithms for recognition of speech in noise.

The contribution of changes in F0 and spectral tilt to increased intelligibility of speech produced in noise

“…Lombard speech has been found to be more intelligible than speech produced in quiet when both are mixed with noise at the same SNR (Dreher and O'Neill, 1957;Summers et al, 1988;Junqua, 1993;Pittman and Wiley, 2001;Lu and Cooke, 2008). Apart from an increase in speech level, these and many other studies (e.g.…”

“…The scale of these changes varies with background noise level (Dreher and O'Neill, 1957;Summers et al, 1988;Tartter et al, 1993;Steeneken and Hansen, 1999;Lu and Cooke, 2008). In addition to these primary changes, acoustic-phonetic modifications in consonant-vowel energy ratio and formant frequencies have been reported.…”

“…Junqua (1993) and Womack and Hansen (1996) reported a shift of energy from consonant to vowel while Hansen (1996) observed energy shifts from semivowel to vowel and consonant. The first and second formant frequency (F1 and F2) also shift, with the consensus that F1 tends to increase (Summers et al, 1988;Lu and Cooke, 2008) while F2 has been reported to increase (Junqua, 1993) or decrease (Pisoni et al, 1985).…”

Predicting head-marking variability in Yucatec Maya relative clause production

“…Transmitting a message in a way that will be intelligible to the hearer is, of course, a prerequisite for successful communication, and it is generally agreed that some aspects of utterance planning must therefore be infl uenced by the intention to be understood. For example, speakers will typically speak louder in noisier environments (van Summers, Pisoni, Bernacki, Pedlow, & Stokes, 1988 ) or modify their vocabulary and speech style when speaking with children (Snow, 1977 ). While such adjustments are arguably the consequence of communicative goals, it is less clear whether these goals can infl uence the decisions made during incremental linguistic encoding.…”

Estimating the spectral tilt of the glottal source from telephone speech using a deep neural network

“…Spectral tilt originates from the glottal excitation generated by vibrating vocal folds; smooth closing of the vocal folds results in a large spectral tilt and a more abrupt closing gives a glottal flow with a small spectral tilt. Spectral tilt has been analyzed, for instance, in studying linguistic stress, 1 phonation type, 2 vocal effort, 3 and speech intelligibility improvement. 4 While previous studies have measured the spectral tilt mainly in order to parameterize and classify speech production, tilt analysis can also be used to modify the speech signal, for instance, by changing its vocal effort characteristics.…”