I tried playing an 11 hour ocean wave track on a loop last Tuesday because my brain wouldn't shut up about work. Turns out my phone's speaker crackles after like 4 hours and the static woke me up twice before I finally killed it. Anyone else have a sounds app that randomly glitches or am I just cursed with a cheap phone?
Flip the volume all the way down to like 25% and put the phone face down on a pillow. The crackling is probably the speaker cone vibrating against the desk or table. I had the same issue with my old phone and that fixed it, no app needed. Also check if your phone has a built in sleep timer or equalizer setting, some of those cheap ones boost bass at low volumes which makes the static worse. If you're still getting glitches after that, record the ocean sound yourself on your phone, way less compressed, and loop that instead. Trust me, the raw audio files dodge most of the weird software crap.