I own a Samsung Note 2 (NT-N7105T), I recently downloaded the latest version of Android 4.4.2. Since downloading the audio output has been scratchy and distorted and piss poor on all apps including Music, YouTube and radio but only when the earphones are plugged in to the device. The inbuilt speaker has good output quality.
This problem has only come about since the upgrade software has been installed.
I have done the following in trying to fix the problem.
1. Tested the earphones on other devices = O.K.
2. Used another set of earphones with a 4 contact 3.5mm pin connector = OK
3. Done the wiggle test with the pin in the jack = still failing
4. Cleaned out the cache on the device = Fail
5. Started device in Safe Mode = Fail
6. Done a factory reset = Fail
I still have audio through the earphones which is monstrously distorted and unlistenable.