Why do our phone calls sound tinny?

21:19, Jun 07 2012
Hakan Eriksson
THE EXPERT: Ericcson's Hakan Eriksson knows how phones work.

Given the amount of data that can be sent over copper lines and to mobiles seems to be doubling every few years, how come the quality of most phone calls is so poor and we aren't enjoying CD-quality sound?

Who better to ask than Hakan Eriksson, the former chief technology officer of Ericsson, the world's biggest telecommunications equipment supplier, over a somewhat crackly line to Auckland?

Eriksson, who is no relation of Ericsson's 19th-century founders, has taken up a new role as head of the Swedish company's operations in Australia and New Zealand.

One of his first jobs is likely to be attempting to persuade Telecom to turn away from its traditional technology partner, Alcatel-Lucent, and select its technology for its much-touted 4G customer trial slated for later this year.

Eriksson acknowledges, if somewhat grudgingly, that the industry has made less progress improving the quality of phone calls than it has putting phones and smartphones in people's hands.

"I can to some extent agree that the innovation has been more on creating capacity on the voice side than creating quality," he says.


"When I started there were about 10,000 mobile subscribers in the world and now there are 6 billion and it used to cost a dollar a minute and now it costs a few cents a minute to call somebody, so technology has accomplished something, but the focus has been on increasing capacity instead of a quality increase."

He believes that is partly down to phone users themselves. "There are technologies available to make voice calls much better, the question is are people prepared to pay for it?"

More than 20 overseas carriers, including Telstra, have endorsed a new technology, Adaptive Multi-Rate Wideband (AMR-WB) Voice, also known as HD Voice, that is designed to make mobile calls less "tinny" by supporting handsets that are able to encode a wider range of frequencies – the high and low tones of the human voice that are usually cut off in calls.

Ericsson, which has been promoting the technology, has likened the improvement as akin to the difference between AM and FM radio.

However, Eriksson says adoption is a case of "chicken and egg", since people at both ends of a call need to have phones with good enough speakers and microphones and each of their carriers needs to support the standard for either party to get any benefit.

Nevertheless, Eriksson is opposed to the New Zealand Government closing the circuit by, for example, mandating carriers support AMR-WB as a condition of them bidding for 4G spectrum this year or next.

Economic Development Ministry radio spectrum manager Len Starling says that is not something the ministry is actively considering.

Instead, Eriksson believes operators will get there in the end. "I would probably not mandate or regulate something. Probably it is better that the industry does what it wants to do."

Even with the adoption of AMR-WB, carriers could still only allocate a paltry 12 kilobit channel to voice calls, while landlines generally support a still small 64kbps channel.

These are, respectively, about a thousandth of the carrying capacity of the "pipe" that could potentially be provided by 4G and passive fibre-optic networks. Networking giant Cisco says it can provide CD-quality audio on its video-conferencing systems using a 264Kbps channel.

The bandwidth allocated to calls limits the frequency at which slices of speech can be sampled and encoded into a phone call. These slices have to be stitched together into something resembling a voice at the other end of the call.

Former Telecom International chief executive Anthony Briscoe says that if fixed-line carriers used the 64Kb channel available to them to full advantage, the quality of calls could be a lot better. But competition between intermediaries has forced the wholesale price of internationally-routed calls down to not much more than a cent a minute.

"Because it is such a price sensitive market, people in the wholesale market will shop around for the best rates and quite often the way that is provided can be suspect," he says.

"Often mobile calls have a lot of `dead air' because calls have been routed halfway around the world. In the past, calls were point-to-point. If you were calling the US you would go to AT&T. Now if you were calling the US, it might go via Germany."

While the technology is available to make improvements, the forces of marketing may be pulling in the other direction, Briscoe says.

"There is a `race to zero' going on – there is no question in my mind. Whatever industry you are in, cheap often equates to not great quality."


By 2017, half of the world's population will be within coverage of 4G mobile networks, 85 per cent will be in range of 3G networks and 3 billion of the world's 7.36 billion will own smartphones, up from 700 million last year, Ericsson forecasts.

The Swedish firm said in its annual "traffic and market report" that the volume of data transmitted across mobile networks would increase by then to about 8 exabytes a month, about 15 times last year's levels.

An exabyte is a billion gigabytes. Cities would generate 60 per cent of the traffic, it said.

Contact Tom Pullar-Strecker
Infotech editor
Email: tom.pullar-strecker@dompost.co.nz
Twitter: @PullarStrecker

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