How should environmental sound be characterised?
An environmental sound is non-speech and is not a in the context of sine tone, pink noise, or white noise often used in psychoacoustics experiments and evaluations, but any other sound is non-discrimination (Dick et al., 2016). Human non-speech sounds or environmental sounds are not intentional communicative. Speech has a fairly rigid temporal frame whereas environmental sounds have huge range with semantic identity unambiguously conveyed extremely quickly (a cork pop) to quite slowly (buttering toast) (Dick et al., 2016).
The main function of human auditory is to perceive environmental sounds. Environmental sounds are greatly heterogeneous in terms of their acoustic and source characteristics and may include natural and man-made sounds such as human and animal vocalisations, water and weather-related events, mechanical and electronic signalling sounds. In controlled laboratory conditions of an anechoic environment, sound intensity decreases 6dB for every doubling of distance according to the inverse-square law. Daily environments are not anechoic and there are numerous possible cues that vary with distance from a listener, such as spectral shape, reverberations, binaural cues, and onset and offset cues. In addition, most waveforms of natural sounds are dynamically changing and have gradual onsets and offsets. The impact of these onsets and offsets on loudness has been described well in Schlauch (2004) (as cited by (Florentine et al., 2011).
A practical way to characterise environmental sounds are to analyse them along acoustical, perceptual, and conceptual dimensions to obtain information that may be useful. Hearing requires transformation of an acoustics signal from a time-varying acoustics waveform into a perceptual representation which is then converted to an
abstract representation that combines the extracted information with information from memory storage and semantic information. The abstract representation is interpreted to guide decisions and to determine responses.
Dick, F., Krishnan, S., Leech, R., & Saygin, A. P. (2016). Environmental Sounds. In Neurobiology of Language (pp. 1121-1138). Elsevier. http://doi.org/10.1016/B978-0-12-407794-2.00089-4
Florentine, M., Popper, A. N., & Fay, R. R. (2011). Loudness. Springer New York https://doi.org/10.1007/978-1-4419-6712-1