[MikeD22j]

Scenario: Playing music with earbuds or external speaker (wired). When the screen goes black, there is noise and the music actually slows down. If I wake up the screen, the noise stops. This only happens with something plugged into the audio jack.
Any help is appreciated.

[B. Diddy]

Welcome to Android Central! A reboot doesn't help? Try wiping the cache partition: Reset: Samsung Galaxy S 4 | T-Mobile Support. If that doesn't help, see what happens if you boot into Safe Mode (steps are also in that link). Safe Mode temporarily prevents all 3rd party apps from starting up. Try listening to your music again--if it works fine, then some other app you installed might be interfering. You could then start opening apps one by one to see which one causes the problem.