The White Noise of Smell
Frosty P. writes "Scientists have discovered a new smell, but you may have to go to a laboratory to experience it yourself. The smell is dubbed 'olfactory white,' because it is the nasal equivalent of white noise, researchers report in the journal Proceedings of the National Academy of Sciences. Just as white noise is a mixture of many different sound frequencies and white light is a mixture of many different wavelengths, olfactory white is a mixture of many different smells. In a series of experiments, they exposed participants to dozens of equally mixed smells, and what they discovered is that our brains treat smells as a single unit, not as a mixture of compounds to break down, analyze and put back together again."
White noise is actually not perceptually neutral noise. It's mathematically random noise, with a flat power spectrum, meaning that for example the sound energy between 25-75 Hz is the same as that between 15000-15050 Hz. But because the human ear's perceptual loudness curve is not flat, the perceptual frequency distribution of white noise is not actually flat. To produce perceptually neutral noise, you need to apply the inverse of the human ear's perceptual loudness curve to white noise, which results in grey noise.
But beyond that, it seems they actually mean something different, more like "perceived as indistinct background noise". That's a wider range of things, and has to do with being able to resolve specific, distracting components, not necessarily with mathematical definitions of noise.
10 PRINT CHR$(205.5+RND(1)); : GOTO 10