Cisco fuzzy voice

Cisco IP phone users are complaining about voice quality only on G.722 calls. Looking for the ways to improve it. There is this discussion, that comes close to what we experience: https://supportforums.cisco.com/message/3205941#3205941 Probably we should try to disable G.722 and downgrade G.711, as there are no control available for input gain in IP phone that probably is a source of "fuzzy" voice.