http://gpfault.net/assets/post-audio/perlin-sound/white.ogg
http://gpfault.net/assets/post-audio/perlin-sound/noise-2.og...
Results (not sure how long these will live):
http://media.io/x-accel-download/noise-2.mp3?ae6b6860-3860-1...
http://media.io/x-accel-download/white.mp3?f6293100-3860-11e...
This, from what I recall, was an intentional choice to disincentivize developers from making the "easy choice" to ship assets in the same format+codec for all devices, where such a format would burn the iOS device's battery doing CPU decoding. Instead, most developers will choose to separately encode their assets for iOS, so that they can use the iOS media frameworks—which coincidentally means that they'll be using the efficient hardware encoding and not burning much battery at all.
However, you can ship custom CPU decoding in your app if you want (e.g. VLC.ipa).
Websites, obviously, aren't (usually) built for single architectures, though, so it's a bit of a pain for them. Larger web video providers (most porn sites, for example) keep iOS-specific encodings on their CDN and try to detect the browser's user agent to decide which version to deliver. Other providers just give up on the concept and build specific iOS-specific apps in order to ensure the correct media is delivered (this being why there are more "video-sharing site" apps for iOS than for Android.)
I used to love it for sleeping, it's rather relaxing.
That said, after about 15 to 30s of attentive, continuous listening, it started making me increasingly uneasy, as I perceived the sound as being extremely oppressive and ominous, in a very chthonian way. I'm not going to try to listen to that any longer because I'm half sure that could almost turn into a panic attack of sorts or something. Really unsettling.
The second, fractal one didn't produce that effect unless I turned the volume way up, and even then, not as much.
play -c2 -n synth whitenoise band -n 100 24 band -n 300 100 gain +20
I could not have been more wrong. There is very clear structure in Perlin Noise. Great write-up and I learned something.
Spectra of the 3 noise samples: http://imgur.com/a/gaiVm
I haven't read up on perlin noise recently enough to know whether that's inherent to its structure or whether there's a more mundane explanation like distortion or encoding tomfoolery.
That would be equivalent to this approach, right?
It might sound/be more natural/fractal than pure white noise (+LPF), I can't tell. But it won't work to drown out office chatter because its the high freqs there that matter.
In particular, it seems like it would have some nice properties for melodies since it will keep the melody in a comfortable range and won't throw in a bunch of large leaps.
If so, what would it look like to use Perlin noise as the input to an inverse FFT function?