Found it!
this is something I can use, a mix of sounds that can help me focus or relax
Hearing Test by Tinni User Reviews
Is Hearing Test by Tinni Safe?
Not enough ratings yet to assess Hearing Test by Tinni.
Is Hearing Test by Tinni Legit?
Hearing Test by Tinni appears legitimate, with a few gaps. AppsHunter Legitimacy Score for Hearing Test by Tinni is 65/100.
Based on 65 of 100 points across 7 verification signals from App Store and developer data.