What is High Definition (HD) Audio?

High Definition (HD) Audio, more commonly referred to as HD Voice in the telecommunications industry, represents a significant improvement in the sound quality of phone calls. It delivers conversations that are dramatically clearer, richer, and more natural-sounding compared to the muffled, narrow quality of traditional telephone calls.

The technical term for the technology behind HD Voice is wideband audio. This name comes from the fact that it captures and transmits a much wider range (or "band") of audio frequencies from the human voice.

• Traditional "narrowband" calls only transmit a very limited frequency range (300 Hz to 3.4 kHz), cutting off the higher and lower tones of a person's voice.
• HD Voice or "wideband" calls capture a much broader spectrum (typically 50 Hz to 7 kHz or more), preserving the nuances and richness of the speaker's natural voice.

This enhanced audio fidelity makes it easier to understand conversations, recognize speakers, and distinguish between similar-sounding words (like "s" and "f"), which reduces listening effort and "phone fatigue."

The superior quality of HD Audio is achieved through the use of advanced audio codecs. These codecs, such as G.722 and the more modern and versatile Opus, are specifically designed to process this wider frequency range and deliver high-fidelity sound efficiently over an IP network.