Many Google Pixel and Pixel XL users have been experiencing severe microphone issues
Some users have also reported solving their problem by using the time-tested trick of heating the phone with a hairdryer, but this isn't a recommended solution, as it can cause other mechanical failures. While Google hasn't yet identified the cause, it has suggested dropping the device could be at least partly to blame. Whether it's users' fault or not, however, the company advises affected users to send in their devices for a free replacement.
Hardware problems in smartphones appear to be ever more common these days, and the Pixel seems to be no exception. Still, it's worth noting that it's far from the worst such problem to happen in recent years – LG and Samsung take the cake on that front. Google also seems to be paying a lot of attention to the problem, and is actively answering to customer queries on the forum, so props to them for that.
source: Google Support Forums via Android Police
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