Vocal effort with changing talker-to-listener distance in different acoustic environments

Abstract

Talkers adjust their vocal effort to communicate at different distances, aiming to compensate for the sound propagation losses. The present paper studies the influence of four acoustically different rooms on the speech produced by 13 male talkers addressing a listener at four distances. Talkers raised their vocal intensity by between 1.3 and 2.2 dB per double distance to the listener and lowered it as a linear function of the quantity "room gain" at a rate of -3.6 dB/dB. There were also significant variations in the mean fundamental frequency, both across distance (3.8 Hz per double distance) and among environments (4.3 Hz), and in the long-term standard deviation of the fundamental frequency among rooms (4 Hz). In the most uncomfortable rooms to speak in, talkers prolonged the voiced segments of the speech they produced, either as a side-effect of increased vocal intensity or in order to compensate for a decrease in speech intelligibility.

Effects of talker-to-listener distance on tone

“…Log intensity increases monotonically with TLD. This effect is consistent with previous literature (Eriksson & Traünmuller, 2002;Liénard & Benedetto, 1999;Pelegrín-García et al, 2011;Thompson & Webster, 1964;Traünmuller & Eriksson, 2000). Within the range of tested TLDs, the increase in log intensity in response to TLD is linear.…”

The effects of language learning and vocal training on sensorimotor control of lexical tone

“…Shih and colleagues found that adaptive tone identification training was most beneficial for adult L2 Mandarin learners. The stimuli were monosyllabic Mandarin words recorded at different talker-to-listener distances (TLD; Cheyne, Kalgaonkar, Clements, & Zurek, 2009;Pelegrin-Garcia, Smits, Brunskog, & Jeong, 2011). The speech files of a word recorded at different TLD were used to represent the variations in lexical tone a listener could hear from Mandarin speakers.…”

A comparison of front-end compensation strategies for robust LVCSR under room reverberation and increased vocal effort

“…While the cause behind the vocal effort increase is different for Lombard speech and speech produced in reverberant distant speaker-to-listener conditions, the impact on speech production parameters is, due to the physiological mechanisms, in many aspects similar. Increased subglottal pressure and tension in the laryngeal musculature in higher vocal effort cause increase of mean fundamental frequency F0 [21], which has been observed for both Lombard speech [8] and distant speaker-listener speech [4]. Increased vocal effort is typically accompanied by the jaw lowering, which results in the upward shift of the first formant F1 in frequency [22].…”

“…Not only can reverberation cause signal distortion, it also results in increased vocal effort of the speakers [4]. This is due to the fact that room reverberation decreases speech quality and intelligibility, which in turn induces changes in the auditory feedback process.…”

“…Consequently, speakers increase their vocal effort to compensate for the drop in intelligibility. This increase in vocal effort, which is a function of both reverberation time (aka T60) and talker-to-listener distance [4], has been shown to be a major source of speech signal variability that can ultimately deteriorate performance of ASR.…”