Telstra's Discovery 2

The Telstra Easy Touch Discovery 2 is a 3G phone built by ZTE but doesn't have HD Voice

Some time ago Orange launched a service they called HD voice. My immediate reaction was “why don’t they call it by the proper name”.  The next impulse was to want it.

Wideband Adaptive Multi Rate is also known as AMR-WB

Look for the HD voice logos on big button mobile phones and you'll be disappointed

That proper name is Wideband Adaptive Multi-Rate and I think in just typing it I’ve answered my first question. Even geeks shorten it to AMR-WB. It’s a technology which makes mobile phones sound better and for those of us with hearing loss that’s very important. There is more to making phones easier to hear than just making them louder. Especially as “those with hearing loss” means a huge number of people. According to the RNID over half the population over 60 has some level of age related hearing loss, and a study by the  Baltimore Longitudinal Study on Aging which looked at people from 20 to  90+ and which looked at over 1000 men over a period of 30 years and women for  17 years  found a significant decline in hearing which accelerates above age 20 to 30 in men, and above age 50 in women.

Phones are for making phone calls

The only widely available 3G big button mobile phone is the Doro 615

It’s trite to think that all an older person needs is a big button mobile phone. The audio side cannot be ignored. Unfortunately you can’t buy a big button phone with HD voice just yet. Nearly all large button phones are 2G, and HD Voice needs 3G. While Raku Raku in Japan uses 3G, there are precious few other 3G phones for seniors. Exceptions are the Telstra Easy Touch Discovery 2, made by ZTE is only available on the Australian Telstra network. The Doro 615 is a freely available 3G big button phone but while it has the right audio circuitry to support the improved sound quality of HD voice, it’s radiochip set does not have the right  CODEC.

A Codec is the part of the phone which turns your voice from the analogue sound waves you speak into the phone into the digital signals used to send the sound over the air. The way a GSM (2G) phone works is that it shares the airwaves with up to six other phones in your area. All the phones use the same frequency. This is known as Time Division Multiple Access, or TDMA. The phone records your voice, waits for its slot and then plays the recording over the air at eight times the rate at which you said it. As each slot is only 45 microseconds you don’t hear the delay.

At the other end the recipients phone takes the squashed packet of voice, unpacks it and plays it at a slowed down rate. This is where the word Codec gets its name, it’s a squashed up term for Compression/Decompression.

Naturally the Codec has to be the same at both ends so that the decompressing one can understand what was compressed in the first place. The quality of the sound depends on a number of things. When your voice is converted from analogue to digital it’s sampled, the codec listens at a set interval and takes just bits of your voice. The closer those bits are together the better it sounds. The tone is limited chopping out high and low frequencies. When the standard was released in 1972 GSM was pretty much a European thing and it was optimised for the German, male voice. When America started to adopt 2G a new way of compressing the information was added, but it’s still old technology designed for the chips of the time, but it’s hard to change as all the new phones had to talk to the old ones. The decoding can be done in the mobile phone network – and this is what happens if you call from a mobile to a landline – but it would still need all the mobile networks to understand the new codec.

When 3G came along there was an opportunity to define a better standard, and this is where Wideband AMR came in. Carrying your voice costs the mobile phone network money, so they are torn between making it sound as good as possible, which means more data, and compressing it to less data but not sound as good, so there are nine different levels of quality, some of which are specially designed for the elimination of background noise.

Blocking out the background

This works very well with noise cancelling technology. A system which was well described by Ron Schaeffer at the Senior market Mobile 2010 conference. You can watch his video here:

The adoption of HD voice has been disappointingly slow, perhaps because the kind of cool people who have smartphones don’t use voice that much, and have less of a need for high quality voice. We are seeing a drift towards smartphones for everyone, and as that means smartphones for seniors we’ll see an increasing number of 3G devices which in turn offers the possibility of HD voice.

Perhaps the greatest indication of the mobile phone industry’s lack of interest in voice for future products is that in the specification for 4G, a system which is already available in many parts of the world, there is no standard codec. They forgot that some people actually use their mobile to make phone calls.

Simon Rockman