HD Voice Call: What is It and How does It Work?

VoIP has become a fixture in the business world.  Since its inception, it has become commonplace in both business and domestic environments and VoIP service suppliers have multiplied in number and reach.  VoIP calls are now used to connect individuals and groups locally, regionally and internationally. The benefits of VoIP are well-known, the major being that it lowers operational costs by transferring communications from analogue lines supplied by a PSTN to digital calls over the Internet, thereby bypassing the toll charges levied by the PSTN operators.

Ealy complaints around VoIP calls were usually about quality end connectivity.  Calls could drop unexpectedly because of networking problems.  Calls could be difficult to set up and of poor quality. Over time these issues have been addressed and resolved, and HD Quality voice and video is being rolled out to new and existing installations.

What is HD Voice?

HD Voice

HD Voice, also known as high-definition voice or wideband audio, is a technology that enhances the quality of VoIP calls by providing richer, clearer, and more natural sound reproduction. It aims to improve the overall audio experience during phone conversations and reduce the limitations of traditional voice calls.

How Does it work?

HD call work

HD Voice works by increasing the audio frequency range and the amount of data transmitted during a call. Traditional voice calls, using the narrowband audio codec, typically transmit audio frequencies between 300 Hz and 3.4 kHz. In contrast, HD Voice extends the frequency range up to 7 kHz or even higher, capturing a broader spectrum of sound.

To achieve this, HD Voice utilizes a wider audio bandwidth and employs advanced audio codecs, such as Adaptive Multi-Rate Wideband (AMR-WB) or Enhanced Voice Services (EVS). These codecs encode and compress the audio signals more efficiently, allowing a greater amount of data to be transmitted over the network.

When two devices supporting HD Voice connect for a call, they negotiate the use of a compatible codec. If both devices support the same codec, the call will be established in HD Voice mode.

What Do You Need?


HD Voice relies on several underlying technologies to ensure its effectiveness:

  1. Enhanced audio codecs: These codecs provide better audio compression and decompression algorithms to transmit a broader range of frequencies.   Your VoIP service supplier can supply the Codecs you need, or in some cases,  they are supplied by the VoIP hardware or software equipment manufacturer.

  2. Wideband audio support: The voice network infrastructure and both the calling and receiving devices must support wideband audio to maintain the HD Voice quality throughout the call.

  3. Network capacity: HD Voice requires a network with sufficient bandwidth to transmit the increased amount of data. Upgrading the network infrastructure is often necessary to accommodate HD Voice calls. This is crucial.  Insufficient bandwidth will prevent HD Voice from operating and may affect the levels of service provided to other applications.

    A corollary is that if you use QoS to manage network traffic,  the QoS levels may need adjustment.

  4. Device compatibility: Both the caller’s and receiver’s devices must support HD Voice and be configured to use it during calls. Compatibility may vary depending on the device model and network operator.

How to Implement HD Voice Calling

HD Voice Calling

Implementing HD Voice Calling involves the following steps:

  1. Network Assessment: Evaluate your existing network infrastructure to ensure it can support HD Voice. Check if your network has the necessary bandwidth capacity and supports wideband audio transmission. If needed, upgrade your network equipment and infrastructure to accommodate HD Voice.

  2. Codec Selection: Choose the appropriate HD Voice codec(s) to be used for encoding and decoding audio during calls.

  3. Network Upgrades: Upgrade your network elements, such as switches, routers, gateways, and servers, to support HD Voice codecs and wideband audio.

  4. Enable HD Voice in the Network: Configure your voice network to enable HD Voice calling.

  5. Device Compatibility: Ensure that the devices used by callers and recipients are compatible with HD Voice.

  6. Testing and Optimization: Perform comprehensive testing of HD Voice calling to verify audio quality, compatibility, and network performance.

  7. User Education: Educate users about the benefits of HD Voice and provide instructions on enabling HD Voice on their devices.

  8. Network Interoperability: Collaborate with other network operators and service providers to ensure interoperability of HD Voice calling across different networks.

Remember that the specific implementation process may vary depending on your network infrastructure, devices, and technologies. Seeking guidance from telecommunications experts or vendors specializing in HD Voice can provide valuable assistance during the implementation process.

The benefits of HD Voice include improved speech intelligibility, enhanced call quality, and a more natural conversation experience. It is particularly beneficial in noisy environments, as it helps to filter out background noise and deliver clearer audio. HD Voice is becoming increasingly common in modern smartphones and networks, contributing to better voice communication quality.