I've been having this strange issue lately (now running miuiandroid 3.4.5): When I call anyone I can hear him perfectly well but he cannot hear me very well. I tried to investigate the problem myself but to no avail. 1. When I'm sitting on my desk - the other end hears me just fine. I wish it's that way all the time. 2. If I decide to walk in the room or go outside while in-call the other end hears metal echo added to my voice , sometimes words or parts of words are skipped. 3. If I begin talking quickly definitely some words will be skipped. 4. flashed different basebands - 3.2.8 , jlb 12 , 3.3.22 , 3.3.29 , QDT07, 3.4.5 - all the same. 5. tried erasing modem and modem1 with fastboot and flashing 3.4.5 baseband - nothing changed. 6. audio recorder can record speech if it's slow and clear but if you begin talking quickly or play the music loudly in the room - all sorts of unusual effects will be recorded - dull sound, some metal echo at moments, lower sound volumes, etc. That's all I got for now. If anyone could give me a clue - I will try it out. As a last resort I could send it back to Xiaomi but at least I would like to try any possible solutions first.