I've read quite a few threads here on apple.com and other forum sites about post-iOS 6 sound issues coming and going. I can't count how many different "solutions" everyone's contributed; I half-expected to come across "Then I stand on my head and recite the Pledge of Allegiance and that fixes it."! 😉
Here are the commonalities I've seen and conclusions I've drawn, for what it's worth:
- Whether or not it happened with iOS 5, it seems to be much more prevalent since the iOS 6 update.
- The iOS 6 problems also seem to include increased battery drain and increased phone heat
- For a lot of sufferers, docking/undocking seems to be involved in some way
I feel my case falls under that last bullet point:
My problems with sound happened RIGHT AFTER I plugged my iPhone 4S into my official Apple USB& Plug block combo into an under-the-counter kitchen radio outlet (the kind where you use the extra outlet if you turn a switch on the front of the radio to ON). After texting while charging it there while making my lunch, my phone and the plug block felt unusually warm, and I'm thinking that maybe it was akin to using an extension cord that isn't graded for that kind of power drain.
AFTER making my lunch, I continued to use my phone for texting while it was plugged into an extension cord. I think it continued to get hot from charging it and using it at the same time with this second non-wall outlet. That's when I lost everything but ringer sounds- I lost notification sounds, text clicks, lock clicks, my volume button controls.
Yet my incoming ringer worked. Ringer settings (listening to different ringer samples) worked. Notifications didn't come in, calendar alerts stopped arriving, and notification setting sample ringer selection didn't (all of which leads me to believe that one specific speaker was affected). My phone continued to feel very WARM to the touch. BTW, I was using both cellular (iCloud calendar and alerts) and WiFi (data), they were both on.
I probably tried 80% of the solutions offered in various threads, and none of them worked for me until I......
STOPPED FOOLING WITH THE PHONE AND LET IT COOL DOWN. I don't know if setting it to Airplane Mode helped it cool down faster, (I'll try just leaving it be with Airplane Mode off next time it happens), but once it cooled down, I turned Airplane Mode off and....I got all my sounds back and alerts started popping up on my screen like popcorn!!!
Once I got sound back, I turned all my usual settings back on and then, with both cellular and WiFi on, the phone started getting warm VERY quickly again.
Because I'm at home with WiFi, I'm running an experiment now where I've TURNED OFF Cellular data (Settings>General>Cellular>Off), which restricts the phone from using the internal cellular radio for data purposes and restricts it to using WiFi only for "email, web browsing, and push notifications."
The immediate result in the last half hour is that my phone is MUCH cooler.
So, this sound problem may very well be software (iOS 6) related, but I feel it's also cellular/ data handling related and affects the hardware in a very specific way.
Hope this helps, and I welcome any input on my findings!