Upgrading pulseaudio should be the last resort when trying to fix an audio issues. Usually it is a missing setting, bad configuration, or incompatible hardware which cause such issues. Only if we know for sure that our issue was related to a bug that is now fixed, or in case we need new features added in a newer version we may try to upgrade pulseaudio.
Please also read about usage and limitations of a ppa:
For Ubuntu 12.04 there is a ppa from the Ubuntu Audio Development Team which includes pulseaudio 3.0.:
For latest and development versions of Ubuntu another ppa offers the latest supposedly stable pulseaudio version for testing:
Installing pulseaudio from both ppa may introduce new bugs, and it may become difficult to downgrade later, so you should not be surprised if your sound issue became worse rather than better.