Stochastic Bookmark

abstruse unfinished commentary

about correspondence


Random Observation

We interrupt this hiatus to ponder synaesthetic phenomena.

Not the sort of synaesthesia Nabokov and others memorably describe, coloring sounds, and yet others mimesize, and that's before the feature writers get it. Rather, going the other way, coloring noise, reweighting the frequency spectrum of random inputs away from the uniformity of white noise:

Often, CDs offer `white noise' as background sound to relax, like waves lapping on a beach or wind sounds. Is this actually white noise, or is it something else? Is white noise even a relaxing sound?

Wind, waves, or similar natural sounds are not exactly white noise - often they are closer to pink noise, but they also have additional modulation. Pure white noise is not particularly soothing, perhaps because it is not something we encounter in nature, and our perceptual systems are acutely matched to the natural world. The advantage of a noise signal is that it can mask out more specific sounds - like the neighbors talking, or cars going by - and submerge them in a steady, continuous sound with no abrupt changes to distract or disturb us. Thus, it makes sense that the closest natural matches to white noise, like the slow undulation of waves at the seaside, can form soothing and effective background noise maskers - a natural sound, but containing no suprises or structure to pull our minds away.

Recent downpours reminded me that the sound of heavy rain is one naturally occurring source. But what struck me was that there's an analogous disruption of the visual field, as one watches the spattering in puddles. But travel through a medium involves interference and dissipation that tends to damp out higher frequencies, so that the rippling of waves in deeper waters corresponds to a darker noise. In either case, watching the phenomenon partakes of some of the same soothing effect as listening to it. Spectral analysis of time series may attribute coloration behaviors to the influence of memory embedded in the diffusion process. But power laws corrupt even statistical physics, so the audiovisual correlation I speak of here may well be insignificant.


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