I'm running CyanogenMod 11.0 on my Galaxy S3 I9300, Android version 4.4.2.
I didn't have this issue before installing CM, so I'm thinking it may be a CM sound. Basically, sometimes this sound keeps playing when I have my phone on loud.
It sounds like an error sound, as if I'm trying to complete an action that's not allowed. It plays even when I'm not even touching my screen, and I think there is actually a small issue with my screen.
I'm not too fussed about any issue with the phone, I just want to delete the sound so it can't play anymore! It really drives me mad because sometimes I can't have my phone on loud without this sound playing constantly.
I tried looking and listening to all the sounds on my phone to try and find it, but I didn't have any luck.
The sound can be heard here (at about 0:02):