Hi! I see you're experiencing a situation where audiobooks sometimes keep playing on your Samsung Galaxy phone even after you close the app. I’d like to help you get this sorted out.

To start, when you say you "close the app," do you mean you press the home button or swipe the app away from the recent apps menu? Also, do you notice if this happens with a particular audiobook app (like Audible) or multiple ones? This info will help me narrow down the best fix.

Meanwhile, here are some steps that typically help with audio continuing after closing an app:

1. Stop Playback Before Closing the App
Sometimes closing the app without stopping the audio first lets it keep playing in the background. Try pausing or stopping the audiobook before closing or swiping the app away.

2. Force Stop the App
If the audio does continue, go to your phone’s Settings > Apps > [your audiobook app] > Force Stop. This will completely shut down the app processes, including audio playback.

3. Restart Your Phone
A quick restart resolves many background process issues. Press and hold the power and volume down buttons simultaneously for about 7 seconds to reboot your Samsung Galaxy device.

4. Check Battery and Background Activity Settings
Some Samsung power-saving or battery optimization settings may affect how apps behave in the background. Go to Settings > Battery and disable power saving or enable unrestricted background activity for your audiobook app.

5. Clear App Cache
Sometimes cached data can cause glitches. Go to Settings > Apps > [audiobook app] > Storage > Clear Cache.

Could you try these and let me know what happens? If you’ve already tried some of these, just tell me which ones, and we can dig deeper or explore other fixes!

Are you mainly using one app for your audiobooks, or several different apps?