A few days ago a problem appeared with my new iPhone 4S running iOS 5.0.1. The speaker delivers sound in some situations, but not (or erratically) in others.
These work properly : ringtone (phone) ; timer and wake-up alarm (clock app).
These don't :
* SMS alerts - most of the time, no sound, BUT sometimes the sound begins to play and stops after a random delay. This happens both for "real" incoming SMSes and when I try the sound from the Settings/Sound panel. It is rare that the sound plays at all, but when it does I cannot correlate it with any other manipulation I might have done.
* iPod : no sound. No volume slider on the screen either. When I plug the earphones, they get the sound, and the volume slider appears. Unplug the earphones, both the sound and the slider go away.
Some radio app I use : No sound, but interestingly a message that says "No Volume Available" where the volume slider normally is.
In general I suspect that no other app can produce sound any longer. I think that with the exception of what I listed above explicitly, no sound is output by the speaker any longer.
No the mute button is not switched on.
I tried both a soft and a hard reset, to no avail.
I tried closing all the apps from the dock, to no avail.
Help please ?