alt Hacker Newsstudy aside, pink noise is awful imo - it's perfect if you're calibrating a PA system and need specific power spectral density properties, but bad for my brain. if sleeping somewhere without a fan or whatever i use brown noise, it's closer to a lower rumbling.
I really like brown noise at night.
My immediate thought about this article was that I'd love to see this study on brown noise (albeit, with more participants).
Second thought was that, I wonder if some A/B testing with my garmin watch would give signal on this. Life is probably too hectic to get real signal.