Acoustic properties of multi-talker babble

Abstract

Multi-talker babble can function as an excellent masker for speech stimuli in perception experiments. It has a higher degree of ecological validity than other maskers (e.g., white noise, speech-shaped noise), as it is a type of noise that many listeners encounter on a regular basis in everyday life. In addition, maskers constructed from speech have, by definition, acoustic properties similar to that of the signal. While multi-talker babble is used extensively in speech perception research, relatively little work has been done on the fine-grained acoustic properties of multi-talker babble. We present analyses of a number of acoustic properties of multi-talker babble generated by randomly combining phonetically balanced utterances (e.g., amplitude modulation depth, amplitude modulation frequencies, spectral properties, and spectro-temporal variability). In order to gain a fuller understanding of the nature of multi-talker babble, we analyze how the acoustic properties of babble vary as a function of the number (2–20), gender, and native language (English vs. Mandarin) of the speakers constituting the babble components. Future extensions of this work will (a) focus on how these acoustic variables affect speech perception, and (b) provide the foundation for a web-based system for generating customized samples of multi-talker babble noise for speech perception researchers.