The recorder's paradox: Balancing high-quality recordings with spontaneous speech in noisy recording environments

Abstract

While sociophonetic analysis requires high-quality sound recordings, sociolinguistic interviews (Labov 1984) are often conducted in uncontrolled, natural environments to elicit casual speech (Tagliamonte 2006). The effects of room acoustics and background noise on formant measurements, however, have never been systematically examined. To empirically investigate how ambient noise affects recording quality and measurements, a male speaker of English was simultaneously recorded to multiple devices reading 260 carrier phrases. Three naturally occurring background noise conditions ( + 20dB, + 10dB, and + 0dB SNR) were created in Praat 5.4 (Boersma and Weenink 2014) and mixed with the original audio recordings. 10,028 measurements of F1 and F2 were taken at the temporal midpoint of each vowel in each of the four recordings using LPC analysis in Praat. Pearson's r tests in R (R Core Team, 2014) assessed the correlation between measurements from each recording. Main results reveal positive correlations between “noiseless” and + 20dB, and + 10dB SNR conditions for each device, all vowels and both formants. When the signal was not appreciably louder than the background noise (i.e. + 0 dB SNR) correlations significantly weakened. These findings are discussed as they relate to sociolinguistic investigations that need to balance high-fidelity recordings with noisier speaking environments.