Hence the reason why I'm not making a proper review, if anyone prefers normalizing their files at the cost of a (probably) imperceptible degradation for them, let it be. I've tested this app just enough to be sure it was actually 'converting' the file and yes it does. It would not be so if there was a setting in the file's metadata like 'play level' that you could change instantly, but AFAIK this doesn't exist.
As an audio professional, I can't recommend an app that alters files in compressed format (mp3, aac, etc.) as any conversion to a lossy format implies modifications and artifacts and is not advisable.
