Samsung's 4.3 update for the S4 (and potentially some other samsung devices) has caused some issues with playback, one being no sound when listening to music. I have witnessed this myself if a certain combination of settings are used.
Potential Fixes
Potential Fixes
- Disable bass boost and the virtualizer. These features are audio effects that are built into the android operating system. GMMP simply turns them on/off and sets the strength. After the 4.3 update, these effects can potentially not work well with GMMP
- Be sure the GMMP eq is turned on. Just like the bass boost and virtualizer, the android EQ can cause conflicts with playback. Be sure the GMMP eq is enabled in the preferences (prefs -> audio -> equalizer -> use GMMP EQ)
- Try turning off external dsps such as DspManager. Some of these external dsps use the same built in android effects that cause conflicts with playback. You can also turn off external dsps in the gmmp settings (prefs -> audio -> equalizer -> use external dsp)