Re: my galaxy s4 makes noises on its own.. nothing shoon notification screen. what is causing this?
If it's a notification tone (pick notification tones and try each one until you can or can't identify the mystery one with one of them - if it's your default notification tone, that makes it easy), you may have an app set to use notification sound, have notifications off, and slightly bad code. (I have one like that, but I've just been too lazy to track it down. Every so often I get a notification tone, not the default, and no toast or line in the notification pulldown.) It could take a while, looking at the notification settings in each app.
When you find it, turn notifications on, turn sound off, then turn notifications off. If that still doesn't fix it, and you're pretty sure that's the app doing it, turn notifications on, but pick a notification tune you don't use for anything else. If that becomes the mystery sound, email the developer, asking why you can't turn the sound off, even if it's unchecked. (Any app longer than 10 lines of code - which includes every Android app - has at least one bug in it. The perfect programmer hasn't been born yet.)
Facebook
Twitter
Instagram