Dialogic Blog

The Cure to Poor Voice Quality Starts with You

by Alan Percy

Dec 28, 2015 3:42:21 PM

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Earlier today I suffered through another hard-to-understand, distorted conference call organized by a potential vendor. Barely able to concentrate on the topic at hand, the poor voice quality didn’t help the situation and didn’t leave me with a good impression of them or their offering.  Why do we put up with poor voice quality? The “tinny” sounding narrow-band and compressed voice has a cure, but we have to change our habits to escape this curse.

Some Background:

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Every time you pick up your phone (wireline or wireless), the quality of the voice on that call is dictated by decisions make long ago – likely before most of you were born.   Sometime during the late 1950’s, a team of engineers at AT&T made a decision that most of the information in human speech is in the range between 400 and 4,000 Hz and to digitize that speech, they would use 8-bit samples taken 8,000 times per second. This standard of using 64 kilobits/second to transmit speech was the foundation of the digital telephone network introduced to the market in 1961 and remains today.   Commonly referred to as narrow-band voice, the 50 year-old 64kbps standard is the basis for the PSTN land-line telephone circuits, PBXs, voice mail and conferencing services.  Anything that touches the PSTN still uses 64kbps narrow-band voice.

The wireless industry took voice quality to a new low, initially with the now-obsolete AMPS analog cellular service, then a series of digital standards we now call 2G, 2.5G, 3G and 4G.  With aggressive voice codecs, wireless operators can cram a voice conversation down to a 6.4 Khz bit rate, saving expensive radio spectrum.   Add in radio interference and a tiny speaker in your mobile device, and poor voice quality is almost guaranteed.  As we’ve become more mobile, it’s almost as if we’ve become accustomed to poor voice quality – sort of a “Stockholm Syndrome of Wireless”.  We pay good money to be punished.

Fortunately, cures for poor voice quality are within easy reach.

Unified CommunicationsMany of the new UC systems support wide-band or HD Voice codecs, allowing two or more users to hold a conference call with much greater clarity.   Microsoft’s Skype and Skype for Business support either SILK or RTAudio codecs; while Avaya, Cisco and a host of others support G.722, a popular wide-band codec that works well on wireline networks.  The net result is that conferences on these systems deliver a much more natural experience with wide-band audio, making it easier for listeners to understand and participate in the discussion.  But to experience the improved voice quality, you must either be using a HD Voice telephone or a web-client to connect to the system.

Wireless and VoLTE – The wireless operators have approached the challenge with two approaches.  The first approach was to support the AMR-WB codec on select wireless devices in the existing digital wireless system.  Led by Orange, this solution essentially squeezed more fidelity through the existing network, but only a limited improvement in quality and required that both callers are on the same network to experience higher-fidelity calls.  The second approach is now emerging with Voice over LTE (VoLTE), which moves voice to the data network provided with LTE carriers, again using AMR-WB, but with more flexibility to provide a superior voice experience to users.  VoLTE also promises to extend the improved voice quality to caller on different wireless networks (as long as both network support VoLTE).  But, if you call a non-VoLTE handset or a land-line, the call reverts back to narrow-band voice.

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WebRTC – Applications based on WebRTC are also a potential solution to improving voice quality.  Supporting the Opus codec for voice, WebRTC applications can potentially offer a much greater fidelity with near-CD quality (if needed), allowing applications to pass music and other highly-complex audio with little distortion.  With virtually every PC potentially supporting WebRTC, the number of possible end-points is enormous.   WebRTC on mobile devices is not quite caught up, requiring mobile users to download “apps” to achieve higher fidelity.  It’s envisioned that social applications like Facebook and others will support WebRTC and wide-band Opus codecs, allowing multi-party voice and video calls from PCs and mobile devices.

All of these are viable options to cure poor voice quality, but the cure starts with users choosing a communication platform that supports HD Voice.  As long as people keep using the 1-800 conferencing services, we’ll be stuck with 1950’s voice quality.

To learn more about HD voice, download the Dialogic Whitepaper titled:  “The Growing Importance of HD Voice”

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Topics: Fax