Sony has posted a post on their blog that the new Xperia T is HD voice certified. This feature, for some reason, was not listed on the company’s product page which is why most of us were not even aware of it. It has now been added to the specs page of Xperia T phone. So, what is HD Voice?
It is the biggest advancement in the call quality since the invention of a phone. This feature works best when other person on the call is also using a phone which is HD voice certified. Sony has infact made a page on their website to show how better HD voice sounds. In UK, Three and EE support this feature. [sony blog post] [sony hd voice page]