Harping on the low quality transmissions offered by traditional phone lines is something of a cliché. You won’t find anyone who argues a traditional landline replicates voice quality clearly and cleanly. Instead, we’ve all become accustomed to the distortion, clipping and general fuzziness involved in making and receiving calls from traditional landline phones. And those offer a superb voice quality in comparison to most cell phones. Unfortunately many of us have simply accepted low audio quality as a “cost of doing business” when using telephone services.
And transmissions on traditional land line phones sound positively crisp compared to calls made between cell phones. Since the proliferation of mobile devices, the audio reproduction problems of traditional landlines seem miniscule. In fact, many people have come to believe traditional landlines offer the highest audio quality possible.
This isn’t true.
Wideband Audio in a Nutshell
In the modern telephone services industry we have more precise ways of speaking about the low call quality offered by traditional landline phones, which allows us to come up with superior solutions than “Ma Bell” ever dreamed up.
You see, the human vocal range is pretty sizable, running from 80 Hz all the way up to 14 kHz. By contrast, traditional landline telephones are only able to reproduce vocal ranges falling between 300 Hz and 3.4 kHz. (3.1 kHz when it comes to most cellular phones). The reason traditional landline phones sound a bit fuzzy and indistinct is because they cut off a lot of the low-end of the human vocal range while trimming away nearly half of an individual’s upper range. This aural butchering is significant and accounts for many of the worst problems caused by traditional telephone solutions, including the difficulty inherent in distinguishing between multiple voices on the same line and the exacerbation of problems associated with listening to accents, soft talkers, and other conversational difficulties.
To combat this aural reproduction problem the modern telephone industry developed what’s known as wideband audio.
Wideband audio allows reproduction of audio spectrum between 50 Hz on the low end and at least 7 kHz on the high end, covering nearly the entirety of the human vocal range. The benefits offered by this increased vocal reproduction range are significant, especially when it comes to business applications:
- Significantly cleaner and clearer audio reproduction.
- Increased ability to distinguish between multiple voices on the same call (essential for conference calls).
- Increased ability to understand accented voices (essential for international business).
- A reduction in listening effort required, decreasing the amount of energy, attention and cognitive load humans need to employ simply to understand the other end of their phone conversations.
- Less aural “bleeding” between a speaker’s voice and background noise (such as traffic or wind).
Wideband audio is obviously superior to traditional audio reproduction methods- so why isn’t it wider spread?
The Technology is There
The distribution problem hampering Wideband audio’s adoption isn’t one of technological availability. The powerful G.722 codec (encoder/decoder) allows crystal clear wideband audio between VoIP systems without any problems whatsoever. Its compression algorithm does not require any more bandwidth than an older “toll quality” G.711 codec. The technology isn’t new either: G.722 codec was recommended for adoption by ITU in 1988 (!).
The reason wideband audio hasn’t been adopted yet isn’t due to a problem with new technology; it’s a problem with incumbent technology. Traditional PSTN (public switched telephone network) make use of the TDM (time-division multiplexing) technology and antiquated analogue-to-digital converters within their networks, within device speakers, and within device microphones. Even if you send out a clean and clear wideband audio signal using a high-tech VoIP system, by the time it reaches an endpoint within a traditional landline system it will find itself just as distorted as any other traditional phone call.
This means that calls made within your organization that do not have to cross PSTN can sounds clear because they can take advantage of the wideband audio codecs. But calls that have to go over PSTN will be converted to narrow band even if systems on both ends utilize voice over IP technology and have wideband encoding capabilities.
A change is needed
Since PSTN still performs most call routing functions and carries the most voice traffic – there is no way of bypassing it and ensuring call completion to every phone. One option is to have VoIP service providers peer with each other through different means that rely on newer technology. But that kind of change would be complicated:
- It would endanger the revenues of incumbent telecom carriers
- It would require major changes to regulations that are optimized for PSTN and generally lag behind rapidly evolving VoIP technology
To ensure the superior wideband technology reaches mass adoption we need to accelerate the number of organization’s converting to high quality VoIP systems and implement new call routing options that do not rely on PSTN. With each VoIP system we install we move closer to influencing a change in our telephony landscape.