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Collaboration, Voice & AV · Foundational

Wideband Audio (HD Voice)

Voice transmission covering about 50 Hz to 7 kHz or more, roughly double the bandwidth of traditional narrowband telephony.

Definition

Narrowband telephony is limited to about 300 to 3400 Hz, which removes many consonant cues. Wideband codecs such as G.722, AMR-WB and Opus extend the range to 7 kHz, and super-wideband and fullband codecs reach 14 to 20 kHz. Wideband audio improves intelligibility and reduces listener fatigue, but calls that traverse the PSTN usually fall back to narrowband.

Example

A Webex meeting uses Opus fullband audio, while a dial-in participant from the PSTN hears narrowband G.711.

Exam tip

The PSTN is narrowband, so HD voice benefits only apply end-to-end on IP.

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