What Is HD Voice and How Does It Work?

Learn how voice over LTE drastically improves call quality

Woman using smartphone on the side of a busy road

d3sign/Getty Images

HD Voice is a 4G LTE audio technology offered by mobile service providers that helps reduce background noise while drastically improving the sound quality of your calls. Here's a closer look at HD Voice and how it works.

What Is HD Voice?

HD Voice stands for High Definition voice. It's a Wideband audio technology that offers a superior standard for voice calling. By extending the frequency range of audio signals, HD Voice does two things very well:

  • Produces clearer, richer, and more natural sounding audio
  • Helps to eliminate background noise in any environment

With HD Voice, calls are clearer and crisper. This provides a better experience for everyone on a call, whether you're talking to friends or family or tele-conferencing with business associates at work.

How Does HD Voice Work?

HD Voice is made possible by VoLTE (Voice over Long Term Evolution) technology. VoLTE is the next generation of VoIP, a technology that enables phone service over the internet. VoLTE is similar to VoIP, except that it uses a carrier's LTE data network, not Wi-Fi, to send and receive calls.

The VoLTE communication standard specifically uses the 4G LTE (fourth generation) network, which allows it to transmit voice calls and data at the same time. Unlike calls made over older networks, 4G LTE offers far better sound quality and faster speeds — in most cases, up to 10x faster than 3G.

With 4G LTE technology, the sound quality you get from HD Voice is comparable to other HD Voice enabled services, such as Skype. This means you'll enjoy richer, more human-sound calls with HD Voice as compared to previous technologies.

Another benefit of VoLTE is that you can switch from a Wi-Fi call to a VoLTE call without the call disconnecting.

How Does HD Voice Work to Improve Sound Quality?

Sound quality depends on the quality of audio frequencies. Normally, mobile calls range from 300 Hz to 3.4 kHz. By comparison, HD Voice ranges from 50 Hz to 7 kHz and up. This spectrum covers the entire range of the human voice, which is typically from 1.6 to 4k Hz.

HD Voice also enhances sound quality by increasing the sampling rate (the process of converting a smooth analog signal into a digital signal). Traditional telephony samples audio at 8,000 times per second versus HD Voice which samples at 16,000 per second. By doubling the width of the sound spectrum, callers can hear more depth and nuance in their conversations.

This leap in technology means that the improvement in sound quality is truly noticeable, especially in places where there is a lot of ambient noise.

How Do I Take Advantage of HD Voice?

HD Voice services may only exist in certain cities or area codes. Call your carrier for details.

HD Voice was first rolled out in 2014, and it's come a long way since then. All the major U.S. carriers, including VerizonAT&TT-Mobile, and Sprint, now offer VoLTE as a free service to subscribers in most major markets.

To take advantage of HD Voice (or VoLTE), check if your carrier offers it in your area and if your phone is HD Voice compatible. Most newer phones support VoLTE and it's often switched on by default. If you have questions, contact your specific carrier for details.