I had a similar problem where I had no sound when I tried to Skype my son but found that all I had to do was to plug in earphones, wait a few seconds and pull out the earphones again. The sound was back! Given the number of people experiencing this problem it appears as though the audio of the tablet/phone is 'shorting out'. ? if this is due to static and the act of plugging in and then removing the earphones seems to clear this. If it is due to static then we all need to be careful that the audio doesn't end up permanently damaged. There are other forums on the Net where people are complaining of constant 'crackling' sound coming from the internal speakers which sounds like classic static problems. One person even got a Samsung tech to come out but all he said was that he'd never come across this problem before so didn't know what to do! I honestly believe the problem lies in the fact that the tablet/phone is being affected by static. It's concerning, in that this problem is not confined to one particular model of Samsung phone or tablet and I wonder if Samsung models are suffering from one of the following; poor grounding, bad connections or some internal component. There are 2 kinds of static EMI which is electromagnetic interference - this is the one that you hear like crackling or fizzing coming from your device and ESD which is electrostatic discharge - this is the horrible one that gives you that zap when you touch a metal object because you unknowingly got charged up on the nylon carpet. However funny for others to see you can actually permanently damage your device if enough of a static charge hits it.
Coated cables inside your device should protect against damage from static so perhaps some Samsung devices are not as well protected as others. We all have so many devices in our homes these days and it is essential that we try to keep them apart so that static isn't built up in them. Those of us who have been affected with audio problems should think about where you charge your device or where you leave it when you are home. The one thing I did wrong was to leave my mobile phone on top of my tablet Ensure you use a anti-surge adapter when recharging your device, so this is possibly why my audio stopped working!. Dust is one of the biggest problems for any device because dust particles become charged and can cause your device to not work properly.
I haven't tried using something to discharge the static on my tablet but I would imagine one of the anti-static bags that are used to transport computer parts would do the trick. Sorry to have gone on but sometimes we are in such a rush living our lives that we don't see what we are doing. I hope this has helped.