Defining HD Voice vs HD Audio

Earlier today Doug Mohney of HDVoiceNews issued an interesting tweet;

Briefing with Tier 1 telco on #HDvoice. Product manager started using the useless marketing term #HDaudio. Maybe should use #HDtelephony?

I find myself agreeing with Doug’s assertion that “HD Audio” is not appropriate terminology. “HD Audio” is way too broad a term, and more appropriate used with respect to entertainment than telephony.

In fact, in preparing my presentation for ITExpo back in September I created an image to contrast the evolution of telephony with other technological aspects of the entertainment industry.

There’s a larger version, too. The critical thing to note is the inflection point at 1937. That’s when the nominal audio standards of the PSTN, what we know as “a toll quality call” were cast in stone.

That image didn’t make it into the final presentation, but it does serve to illustrate how consumer audio had improved in dramatic ways compared to telephony.

From a consumer audio perspective HD audio has come to mean something entirely new in just the past few years. Some people are now downloading music recorded at higher sample rates and longer word lengths than 44.1 KHz and 16 bits common to Philips “Red Book” CD format.

I’ve purchased a few albums from HD Tracks. Often these are digitally cleaned up re-masters of older analog master tapes. Sometimes they have copies of the original master tapes made at 48 KHz, 96 KHz or even a whopping 192 KHz sample rates!

There are some a parallels between the emergence of such offerings and the transition to HDVoice. As long as the optical disk was the distribution medium consumer music quality languished. The efforts at the Super Audio CD and DVD-Audio appealing to a very small audience of audio purists. Taking the traditional distribution out of the picture, that is the emergence of downloading music to computers for playback, has been the catalyst of growth in this area.

It’s not unlike VoIP service providers continually relying upon PSTN inter-connection. It defines the quality of service that they can deliver and dooms them to the old business model.

As to the technology, the 16 KHz audio sampling rate that is the baseline requirement of HDVoice seems puny and insignificant when compared to what HD Tracks is offering. Of course, context is important. There’s little reason to use very high sample rates when we’re primarily concerned about human conversation.

Still, I think that “HD Audio” definitely means something well beyond telephony. But what’s in a name?