High-definition (HD) voice calling is an audio technology that delivers a seamless calling experience using wideband audio codecs and noise cancellation. It is a standard feature in many voice-over-internet-protocol (VoIP) systems, providing users with clearer sound quality and reduced background noise in any environment. In this article, we answer the question, “What is HD voice calling?” as well as explore its benefits for small businesses and cover top service providers.
How HD Voice Calling Works
HD voice calling works by using a codec, a computer code that compresses audio content (e.g., voice content) into data packets for easy transmission before sending it to a receiving server. The receiver will then open the packets to decompress the audio content.
The process of converting an analog sound into a digital data format is called sampling, while the rate at which it takes place is called the sampling rate. The higher the sampling rate, the better and more accurate the audio representation will be. Traditional phone systems have a sampling rate of 8,000 times per second, while VoIP systems with an HD voice feature can reach 16,000 per second—drastically improving sound quality.
Sound production and quality also depend on audio frequency. Normally, a standard voice call limits the audio frequency to 300Hz to 3.4kHz, while an HD voice call’s wideband audio transmits between 50Hz to 7kHz or higher. This is much closer to the human voice, which is between 75Hz and 14kHz.
Comparison of VoIP Codec Formats
Understanding codec specifications is useful in comparing the audio quality of different business phone systems. Below we compare the most common codecs used in VoIP software based on frequency, sampling rate, bitrate, and bandwidth used.
Samples per Second (Hz)
300 - 3,400Hz
24 - 30Kbps
300 - 3,400Hz
80 - 90Kbps
50 - 7,000Hz
80 - 90Kbps
10 - 550Kbps
6 - 510Kbps
VoIP codecs determine the bandwidth, compression, and voice quality for VoIP phone calls. Below, we explain more about the key differences between VoIP wideband codecs:
- G.729: Offers a decent audio quality at a low bitrate of 8Kbps. With its low bandwidth requirements, you’ll be able to get more calls using multiple devices.
- G.711: This codec has the highest quality audio encoding that can be transmitted through a public switched telephone network (PSTN) and is used for voicemail and telephone traffic. It supports various voice levels while maintaining high intelligibility.
- G.722: Designed specifically for voice compression, this codec has a high sample rate and bitrate and covers most of the frequency range of human voice. It is not suited for any audio frequency that goes beyond the human speech range, such as music.
- AMR-WB (G.722.2): A widely adapted format in mobile networks and has a superior speech quality due to its high signal frequency and sample rate.
- Opus: A royalty-free and highly versatile codec that has been standardized in web applications due to its super-wideband signal and flexible sample rate. It is unmatched for interactive speech and can efficiently handle low to high-complexity sounds.
Benefits of HD Voice Calling
HD calling offers numerous benefits for businesses and customers, including superior call quality and more productive conversations. Here are the benefits you need to know before investing in an HD-ready phone system:
- Improved audio quality: HD calls use a broader audio range, which captures clearer and crisper sounds. This covers both the high and low pitch of a human voice, leading to more realistic-sounding audio.
- More accurate transcriptions: Low-quality audio directly affects the accuracy of voicemail transcriptions. An HD phone call makes it easy for voice-to-text technology to distinguish spoken words, providing a more accurate voicemail transcription.
- No additional setup: VoIP systems come pre-installed with HD voice codecs and noise cancellation features—no need to install or configure anything. As long as your device fully supports HD voice, you can enjoy high-quality calls on your VoIP phone and apps.
- More efficient bandwidth usage: Codecs improve call quality by using at least 64Kbps bitrate (amount of audio data transferred per second) to reduce bandwidth requirements. For example, a G.711 codec in a VoIP system lets you switch to an HD call without consuming more bandwidth.
- Better customer service: A poor audio experience causes agents and callers to repeat themselves or mishear information, leading to a frustrating customer experience. An HD phone call enhances customers’ perception of your business by ensuring conversations are precise and efficient.
Factors to Consider Before Investing in HD Calls
Moving to an HD voice system is a huge investment for business communications. However, this popular VoIP phone feature comes with a few caveats. Before switching to a VoIP provider with HD voice calling capabilities, here are a few factors to consider:
One way to utilize HD voice calling is to have a fast internet connection. An HD call has a higher data usage than a standard phone call, so your internet connection should be strong enough to support multiple calls simultaneously. Unfortunately, many small businesses, particularly those in rural areas, don’t have access to high-speed broadband because of budget constraints or geographical location.
Ideally, HD voice calls require at least 100Kbps bandwidth. Your VoIP network will suffer if you have network users sharing the same internet connection while engaging in heavy internet activities like video conferencing and streaming. This leads to network congestion, which causes broken audio, dropped calls, or phone echoes. We recommend taking our free VoIP speed test to determine your network’s capability for an HD-supported VoIP service.
HD voice provides crystal-clear voice calls when the caller and the recipient use HD voice-enabled devices. This means you have to check whether your desk phone or mobile device is compatible with HD calling, or you won’t be able to enjoy clearer voice calls.
A device is HD voice-compatible if it works over 4G or 5G long-term evolution (LTE) networks. If you’re using a VoIP desk phone, many desk phone manufacturers like Polycom, Avaya, Cisco, and Yealink all support HD voice.
Getting a business cloud phone service involves a significant investment. VoIP providers and mobile carriers use digital signal processing power to enable HD voice calls. To compensate for the added voice requirements, these companies charge additional costs to their clients in the form of expensive pricing plans. You’ll want to consider the right subscription tier that best fits your needs and budget before committing to an HD voice-ready phone service.
VoIP Providers With HD Calling
While there are plenty of VoIP providers to choose from, not all support HD voice calling. VoIP services use various codecs to compress and decompress audio data, allowing it to travel over the internet efficiently. To help you decide which service provider offers HD calling, we listed the best HD-ready VoIP providers:
Audio Codec Used
Monthly Starting Price (per User)
Frequently Asked Questions (FAQs)
How do I improve audio quality without HD voice capability?
Noise-canceling headphones, quality microphones, and HD voice-enabled mobile phone apps (e.g., Skype) help enhance the audio quality of phone calls. Although they’re not a sufficient alternative for HD voice technology, these tools help improve the call experience.
What are the requirements for HD voice calling?
HD voice calling requires users to have an HD voice-compatible device, a business phone system powered by HD voice, and a high-speed internet connection. In addition, the user should be in an area with HD voice coverage for a better calling experience.
Why do some VoIP providers not support HD voice?
Some VoIP services are limited to the G.711 narrowband codec, which has a lower frequency range of the audio spectrum. They prefer this codec format as it uses packet loss concealment to minimize the impact of packet loss during transmission. Another reason is that network connections with high latency levels cause VoIP services to reduce call quality to achieve a more reliable connection.
HD voice calling delivers an enhanced calling experience to businesses and consumers by providing clearer, natural-sounding voice quality and reduced background noise to phone calls. This leads to higher team productivity, better sales performance, and increased customer satisfaction rates. Now that you understand HD voice calling, discover the difference it makes by subscribing to a business phone provider with HD voice calling capabilities.