Nuraphone is weird, because when I first heard their pitch (“We stick a thing in your ear and measure to get better sound”), it made perfect sense to me: personalization of headphones to individual HRTF is almost certainly the future (Smyth’s Realizer being an extreme example), and so I figured that was what they were doing. Looking closer at how they say it works, however, apparently they use otoacoustic emissions as their major (sole?) test. I’m not an audiologist, so perhaps there’s some nuance I’m missing there, but my understanding was that otoacoustic emissions can be used to determine hearing damage, rather than HRTF. I guess compensating for hearing loss is a pretty useful feature in and of itself, but it’s not what I’d expect.