I'm having the same issue as you guys. Since doing the 4.3 update, my phone produces no sound.
I have Smule's Ocarina app and when I open it, I get the following message:
+Unable to initialize audio+
+Ocarina is unable to work correctly while music is playing or a phone call is active. Please restart Ocarina after pausing the current track or finishing the current phone call.+
I don't know if that helps anyone figure out what's going on here. It's really frustrating to keep missing calls...
Quickstr, you're a genius! I was dreadking having to take the phone in to swap for a refurb! I just don't have the time to be without it!
I went riding the other day and since then I noticed the intermittant sound issue. I remember from the ride I got a bit sweaty and the phone was in my pocket and did have some condesation on it.
I took your advice and just used some tissue paper in the headphone jack and now all good!
It was kinda worrying because I saw another thread where if you press down next to the speaker it would intermittantly work and that was happening too so I thought it was a hardware fault with the speaker connections but since using the tissue in the headphone jack all good!!!
I got my new iPhone 4 two days ago and this morning the sound just stopped working. I had been pressing snooze on my alarm - sound worked first couple of times and then it just went onto vibrate. No sound would work - ipod/ ringtone/ keys etc. I read on the net that it was to do with the headphones so plugged them in and the sound worked through them but didn't solve the problem. This evening it has just randomly started working again. Sounds from above posts that it's to do with the headphones but I haven't even used my headphones yet and defineitly haven't been near any condensation/ water. Strange. If happens again think I'll ask for a replacement as this is not a good start!
I have a one month old Iphone 4. I live in india where its really hot and sweaty. could some droplets of seat permeated through the small jack on the speakers (or receivers) to cause the speakers to stop working? My headphones work and there is volume. It is frustrating as India does not even have a service centre so I have to ship my phone out of country to get it replaced...****
I've had the same problem with a brand new iPhone4 I purchased this week. No sound out of the inbuilt speakers so that the speakerphone, iPod music, key clicks cannot be heard.
I've tried everything - reset to defaults, wipe and restore of phone. I suspected IOS 4.3.3 as the issue, but have another iPhone 4 on this release with no issues at all.
Here is the answer though......
There is only one speaker in the iPhone - its on the bottom right of the handset.
If you squeeze the case between your fingers (put your thumb on the case to the right of the square button and your forefinger on the back of the case and squeeze) while playing music through the speaker you will hear that you can affect the sound - in my case it kicked the speaker into life from nothing.
This has to be a manufacturing fault in my view. The speaker now works all the time - I'm still going to return my phone for a replacement, but just following this proceedeure made the speaker work from being absolutely dead.
Dempsterdavies is completely correct, this has to be a manufacturing/design problem. I've had the exact same issue for over a week now, tried all the suggestions about cleaning out the headphone jack, etc.. with no luck whatsoever. I just tried squeezing the lower right-corner of my phone and instantly the sound started working. I can squeeze it again to get it to turn off. Guess we have a new way to mute the iPhone 4...
I just got a brand new Iphone 4 and everything worked fine except for the speaker, I tried to restore it twice and nothing happened. I followed the instructions given by Dempsterdavies and squeezing the right side of the home button the speaker started to work. I was amazed how simple was to solve the problem thanks to Dempsterdavies !!!
I had the same problem myself.
I took my six months old iPhone 4 to the service because all of a sudden itstarts to show a message "this device is not intended to be use with thetelephone".
I wasn't able to hear anything from the speakers, but I was able to"hear" using the headphones.
Just like yours.
But, did you receive the same message?
If so, pay attention to this:
The service told me, after a week, that my phone was affected my moistureand/or liquids, so the warranty was void and no replacement could be made.
After a 30 minutes arguing with one of the persons there, I took the phonehome.
Since I run out of warranty, I started to check it by myself.
I grabbed a pin and some cotton and start sweeping the USB connector.
After five minutes, yes, five minutes, I was able to fix it.
So now, my iPhone 4 32 Gb is normal, with sound through the speakers.
Check yours if you find some white particles over the connector.
Clean it with the pin and the cotton.
Scratch very gently the connector with the pin.
Make sure you use a direct light source to see it very well. I used a camping head light.
Give it a try and see what happens.
If I can assist you in something else, let me know.
A word for the future: watch out if you use the phone in humidity environments.