Please i need an urgent resolution. I got my Lumia 800 about 2 weeks ago but it has always been one complaint or the other about the audio quality. Please hardly hear me even when i increase the volume to the maximum. They also complain of echo and change of voice. I have abandoned the phone for now because i am constantly embarassed when people ask me if i am whispering when talking to them. Urgent response is needed.
Increasing your volume to maximum won't affect what the person on the other end will hear. They have to turn the volume up on their device! See if you can borrow a SIM card from someone to see if the problem is related to the carrier (most likely) or a faulty microphone.