Customers of Orange and Three can now experience higher quality “wideband” phone calls providing they use compatible phones.

If you’re an Orange or Three customer, you’re now able to experience “high definition voice calls” between two “HD Voice” enabled handsets. “HD Voice” phone transmit sounds with a much larger range of frequencies than standard phone calls (50Hz-7kHz for “HD Voice” calls compared to 300Hz-3.4kHz for standard calls) making it easier to distinguish who is speaking on the phone and determine exactly what they’re saying.

Why is a large frequency range important in audio?

The human voice is made up of a range of frequencies between 80Hz and 14kHz (1kHz = 1000Hz). When we listen to other people speaking or listen to music, our ears combine these different frequencies together and interpret them as sounds or voices. When certain frequencies are missing from what we hear, we sometimes experience difficulties in understand what is being said or who is saying it.

Standard phone calls only transmit frequencies between 300Hz and 3.4kHz. This means a lot of the low & high frequencies in human speech are lost. The removal of those frequencies often makes it difficult to identify who is speaking on the phone (this sometimes causes problems in conference calling with multiple participants). The limited frequency range also means call centre hold music always sounds terrible, background noise is more of a problem and certain words are difficult to distinguish over the phone (e.g. the sounds of ‘s’ and ‘f’ e.g. sailing and failing).

HD Voice phone calls can transmit a larger range of frequencies (between 50Hz and 7kHz). This leads to much better audio quality and makes it easier to distinguish different people and different sounds over the phone. According to Polycom, a company which provides “HD Voice” solutions, “by extending telephone bandwidth to 7 kHz and beyond, it is clear that one can markedly reduce fatigue, improve concentration, and increase intelligibility… this improvement is even more significant in real-world room situations, where the sound is often degraded by reverberation, projector or air conditioner noise, accented speech, and other acoustic problems”.

How does the frequency range of phone calls compare to other technologies?

Creative Commons License photo: Noel Feans

Standard phone calls transmit a much smaller range of frequencies than those which are transmitted over radio, television and audio CDs. “HD Voice” increases the frequency range of mobile phone calls so it better resembles the audio range on TV or radios. However, the frequency range of “HD Voice” is still much smaller than what is transmitted over radio and television.

Technology Lowest Frequency Highest Frequency
Standard phone call 300Hz 3.4kHz
HD Voice phone call 50Hz 7kHz
Radio/Television 30Hz 15kHz
Audio CD 20Hz 20kHz
Professional audio equipment 20Hz 22kHz
Human voice 80Hz 14kHz

Rory Cellan-Jones from the BBC has a audio comparison between a “HD Voice” call and a standard phone call.

What do I need to use HD Voice?

Both parties in the call must have a “HD Voice” compatible handset in the 3G reception area of a “HD Voice” enabled network. Your mobile phone network will automatically switch to “HD Voice” when these conditions are fulfilled.

The “HTC Desire HD” is compatible with “HD Voice” on Orange

At present, only Orange and Three support HD Voice. The following network/handset combinations are supported:

  • Orange: HTC Desire HD, Nokia N8, Nokia E5, Nokia X6, Nokia 5230, Sony Ericsson Elm, Samsung Omnia 7
  • Three: Nokia C7, Nokia E7, Nokia N8

HD Voice calls are charged at the same rate as standard calls. HD Voice is not currently supported on other UK networks.

Can I make cross-network calls using HD Voice?

No. At present it is not possible to make a cross-network “HD Voice” phone call between Orange and Three. According to Three, they’re looking to roll out cross-network “HD Voice” calls in the future so watch this space.

What happens if I’m in a 2G signal area?

If either party is in a 2G signal area, your call will connect as a standard call without using the “HD Voice” technology.

Why is it taking so long for HD Voice to roll-out in the UK?

The standards behind “HD Voice” (technically called AMR-WB or G.722) were agreed as early as 9 years ago in 2002 with the first 3G networks in the UK rolling out in 2003. It could be pertinent to ask why the “HD Voice” roll-out has taken so long in the UK as the technology and infrastructure have both been around for a long time.

You’ll need 3G coverage to use “HD Voice”.

One explanation is that “HD Voice” simply increases costs for the mobile network operator (“HD Voice” calls use about double the network bandwidth per call) whilst at the same time generating no additional revenue for the network (the price charged is the same as for a standard call). Given the effect on the balance sheet of the mobile operators, it is no wonder they’re dragging their heels on HD Voice.

Do voice-over-IP services such as Skype use “HD Voice”?

Yes. Given a sufficiently fast internet connection, most voice-over-IP services such as Skype and “Google Talk” use some kind of wideband-audio technology. Although the technology used is not necessarily the same G.722 codec used for “HD Voice” calls over a mobile network, the effect is the same.

Where can I get a “HD Voice” compatible handset?

Click through either to the Orange or Three websites. The following phones are “HD Voice” compatible:

  • Orange: HTC Desire HD, Nokia N8, Nokia E5, Nokia X6, Nokia 5230, Sony Ericsson Elm, Samsung Omnia 7
  • Three: Nokia C7, Nokia E7, Nokia N8

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