Phone Systems Industry News

What is HD Voice and How Does It Deliver Better Call Quality?

by Sasha Viasasha
November 21, 2017

Once you’ve seen a TV show in HD, it’s hard to look at a show on an old screen. Analog images look so fuzzy compared to the new digital standards. In the same way, HD Voice is resetting expectations for baseline audio. Voice UX is becoming the new battleground for differentiation in the crowded communications sector and HD Voice is leading the charge.

That’s great news for small business owners because now they can afford enterprise level audio quality. HD Voice is being offered by all the major mobile carriers, most VoIP providers and a few hosted PBX partners. In the years ahead, customers will judge your company based on the sound quality of your business phone line. Buzzing, echoes, jitter and dropped calls can drive away customers. HD Voice helps establish your professional credibility.

But what is HD Voice? 

What People Mean When They Say HD Voice

HD Voice is also known as “wideband audio.” Traditional phone audio was stuck in narrowband. People can hear a much wider range of pitches from deep to high and volumes from soft to loud. Pitch is measured in Hertz (Hz) or kilohertz (kHz), while loudness is measured in decibels (dB).

While people with normal hearing can pick up frequencies between 20 Hz and 20,000 Hz (20 kHz), the human voice usually falls in the range from 80 Hz on the low end to 14 kHz on the very high end.

Listen here to the difference between the deep growl of 80 Hz:

and the high squeal of 14 kHz:

Conversational speech ranges in loudness from around 20 to 50 dB.

How HDVoice Delivers a Crisper Voice UX

Traditional, narrowband phones were limited to audio in the range from 300 Hz to 3.4 kHz. HD Voice extends that range down to 50 Hz on the low end and up to 7 kHz on the top end. Next generation audio built on top of HD Voice, such as Enhanced Voice Services (EVS), extends the upper range all the way to the 20 kHz maximum. Higher frequencies are in the “dog whistle” category.

Currently, EVS is only available on a few handsets like the iPhone 8, iPhone X, Galaxy S7 Edge and the LG G5. In the meantime, HDVoice has been deployed by more than 117 mobile carriers in 76 countries. All four of the largest mobile carriers in the US – Verizon, AT&T, T-Mobile and Sprint, in that order – offer versions of HD Voice. Most are conforming to the standard AMR-WB voice codec, except Sprint which is staying with its own EVRC-NW codec for now.

Another way that HD Voice delivers higher quality sound is by taking 16,000 audio samples per second. It replicates voices with digital precision to deliver more nuanced modulations in tone, closer to the experience of hearing speech in person.

The HD Voice options offered by VoIP providers requires office phone system hardware that can make the switch from the G.711 to the G.722 voice codec. Carriers and VoIP providers are now working on interoperability from SIP to mobile and easy answers for transcoding between standards. This is an exciting field and you should expect to see a number of advances in the months ahead. 

The No. 1 biggest development in 2018 will be the arrival of 5G, which will stream voice at 10X the speed of 4G, further improving audio quality, reducing jitter and preventing data loss.

Leading digital transformation

HD Voice is riding the wave of technologies that are turning analog hardware into digital processes. Virtual phone systems are helping businesses go mobile while more than half of companies with legacy PBX systems and one fifth of on-premise IP-based PBX systems are experiencing end-of-life issues. With digitalization, new features and upgrades are maintained in the cloud, and that is becoming more critical as technology cycles accelerate. Telecoms are preparing for this shift by pouring billions of dollars into upgrading their networks to stay ahead of the curve.

Reinventing voice

As voice is better supported by mobility and smart tech, a new user experience is emerging. AI is transforming telecom, from more resilient networks to better call quality and advanced analytics. Spoke Phone is a truly global phone system with DDI's in 56 countries, AI auto-attendent, and smart geo routing. To learn more about Spoke, including how our AI is powering the next generation voice UX, sign up for an interactive demo and see how to transform your mobile phone or business phone line into a smart office phone system.