[A late comment, I realize, but this video is cool. For disclosure: I'm not hard of hearing or have significant vision issues.]<br><br>This makes me wonder if white noise could be compared with luminosity in vision. In that human beings are more sensitive to that then they are with color. And since there's a lot of diversity in color acuity, that can affect how noticeable a color change may be between different people. (I think this is a useful concept with colorblindness accessibility; with a rule of thumb being: can you still read/use the site/UI when it's in greyscale? If not- consider tweaking the contrasts.)<br><br>To bring it back to the video, people definitely also have differing tonal acuity with sound (usually even profound hearing loss allows the person some range of hearing, but often not where it tends to matter, to hearing culture at least). So some tones are met with deaf ears and it's only made worse by the Doppler effect.<br><br>Makes me kinda wish the US got on this by now. As Nicolas Burton pointed out, I think this could definitely benefit the visually impaired.