Soundscape cube: A holistic approach to explore and compare acoustic environments Free

Soundscape patterns result from sounds radiated by several sources governed by diverse processes acting at different scales. Acoustic measurements are sampling this multi-scale variability pattern at particular locations and times. To facilitate soundscape analysis, the identification and separation of the different contributors, and soundscape comparisons, an approach, called soundscape cube, is introduced. For any acoustic measurement time-series, a probability of occurrence is estimated for all time-frequency samples of sound pressure levels (SPL) from the cumulative density functions (cdfs) of the sound spectra computed for consecutive time-windows. These spectral cdfs are then stacked along the time axis to generate a 3D block that piles up the time-frequency surfaces of the spectral SPL quantiles. This soundscape cube can then be explored by various mathematical operators to characterize and separate intra-soundscape SPL patterns emerging across the cube. The soundscape cube can also be split into its ambient-noise and structured-signal components, which respond to different forcing and timespace scales. Inter-soundscape cube operators can highlight the differences and similarities among sites, years,and their scales of autocorrelation, recurrence, etc. Application examples of this approach are given for acoustic measurements from the Canadian Arctic, the St. Lawrence Estuary, and the Mediterranean Sea.