I'll be speaking near the end of the day, on a panel called Mobile VoIP. My point is not that VoIP matters - VoIP is just a technology - but mobile is significant and will drive the tipping point for HD voice.
So far, high definition voice, i.e. wideband audio telecom, has been enabled by most IP-PBX vendors and some VoIP service providers. There are also wideband audio telephone sets available from many providers. But mostly these systems operate as standalone islands. When you call someone outside your island, the audio reverts to PSTN quality.
The problem is IT directors are making the adoption decisions and their budgets have just been cut. Even if the incremental cost of HD voice was zero, why would they sign up for more support hassles?
Once HD voice becomes possible on mobile, the adoption decision flips to individual consumers. They make the choice when they buy their next mobile phone. True, only one mobile operator has announced support for HD voice, and they are in Moldova. But Orange is promising to extend this to their networks in the UK and Belgium and then to all of Europe.
Five years from now, most 3G handsets in Europe will be HD voice enabled and there will be consensus that mobile HD was the tipping point for HD voice.
Note: The tag on Twitter and Technorati is: hdcomms