[dpflan]

Ah, should've grouped things better: the linked Resident Advisor article warns.

"Notch therapy has been around for a while and, as with many tinnitus therapies, its efficacy is disputed. Various online resources can help you explore it for free, but it has also been repackaged and marketed as a (paid-for) app by the likes of Tinnitracks. It's worth treating their miracle-cure claims with scepticism."

(The "Various online resources" is a link to: http://www.notchtherapy.com/)