Hello, I have been having the same problem on the Samsung Galaxy S3. When playing music, the Poweramp volume suddenly drops for just the app. I can temporarily fix the problem by going into the audio settings and setting replay gain source to track (although it was already on track) or changing any of the other replay gain settings. I have also tried disabling DVC but that hasn't really helped the problem. This problem usually occurs between songs; the one playing is fine and the next are all quiet. Also for a side note, I have replay gain tags for each of my songs from Foobar2000.