HD Voice – Kowabunga


I had reason to go down to Thailand to visit an operation there and when I arrived I pulled out my AIS SIM and put it into my iPhone. They have recently upgraded their network to 2100 MHz and the speeds are generally good, averaging about 20 megabits/second download.

I received a phone call later that day and we takes for a while. After a few minutes I noticed how utterly clear the caller’s voice was. It was as if they were in the same room, talking to me. Gone was the fuzziness, and I noted I could clearly distinguish between “S” and “F” and between “B” and “P” and “D” and between “M” and “N”.  It was quite remarkable what a difference it was in quality.

Throughout the day I received several phone calls, and half of them were the usual cell phone quality, which in Asia is still better than in the US. The calls to and from the United States were noticeably the worst. And, then I talked with the first party again and everything was crystal clear…I could even hear and understand conversations in the background.

Being an observer of the obscure, this got me to thinking and pondering why calls seemed to fall into three distinct quality buckets: Poor, Decent, and Superb. I continued to watch and observe to try to figure out what was happening. For calls to the US the easy conclusion to leap to is the great distance and overloaded fiber cables (although this turned out to absolutely not be the case.)

I eventually identified that the quality was great when talking to other AIS cell phone users, when they had iPhones. Ah ha! A little googling led me to exactly what was happening…

It’s called “HD Voice” and was formerly called “Wideband Audio”. Here is a link to information on it and a list of carriers that support it: www.Wikipedia.org/wiki/Wideband_audio

Colin here. Most phone connections are limited to a frequency range of 300 to 3000 Hz. And, this is then compressed down to 6.5 kilobits in the United States or 13 kilobits everywhere else. The result is fuzzy, unclear audio.

HD Voice has a vastly expanded frequency range of 50 to 7000 Hz and an adaptive bitrate. For those of you really into VOIP you may know if the G.722 standard, which is the underlying technology of HD Voice.

I can’t express strongly enough what a profound quality difference it makes, especially if you are used to the worst cell phone audio quality in the world, which happens to be the United States.

I find it ego bashing that HD Voice was first implemented in Moldova (in 2009) and then in Armenia. Fifty-seven carriers and countries later, T-Mobile introduced it in the United States. AT&T is still thinking about it, and Verizon and Sprint are counting on people remaining stupid to it…they have no announced plans to move forward with HD Voice. Today, HD Voice is widely implemented in 66 countries, the United States not being one of them.

You get the benefits of HD Voice not only within a single carrier, but anytime both endpoints support it. Thus, calling into the PSTN or to other countries will give you the quality benefits. Calling to or from AT&T or Verizon will continue to be lousy quality.

I am not sure what the mindset is in the US where quality no longer seems to matter. As an old-timer who is proud of what the US has accomplished it pains me to see us lag other countries by such an extent.  I’ll spare you further editorializing.

Many technologies are over hyped. I can’t say that having a curved TV screen excites me in any way, although it is novel. But HD Voice is real, its profoundly better, and I want it.

I have been a pretty loyal Verizon fan for many years, but currently loving T-Mobile – partly because of HD Voice. (Hey Verizon: Remember when you used to say: “It’s the network”?)

Colin Berkshire