Sample rate is how many times per second a digital audio system measures the sound, given in kilohertz (kHz). The sample rate sets the highest frequency the audio can carry, roughly half the sample rate. Wideband audio is voice audio sampled at 16 kHz, which carries frequencies up to about 7 kHz, roughly twice the range of a traditional phone call. That extra range makes speech clearer and much easier to understand.
Audio bands at a glance
| Band | Typical sample rate | Approx. voice range carried | Where you hear it |
|---|---|---|---|
| Narrowband | 8 kHz | 300 Hz - 3.4 kHz | Old landlines, basic PSTN dial-in |
| Wideband ("HD voice") | 16 kHz | 50 Hz - 7 kHz | Many VoIP phones, HD voice calls |
| Super-wideband | 32 kHz | up to about 14-16 kHz | Modern UC apps and headsets |
| Fullband | 48 kHz | up to about 20 kHz | Music-quality audio, high-end codecs |
Why it matters
Consonants like "s", "f" and "th" carry most of their energy above 3.4 kHz. On narrowband audio, "fifty" and "sixty" or "f" and "s" can sound alike. Wideband and better audio:
- Makes speech easier to understand, especially with accents or soft talkers.
- Reduces listening fatigue in long meetings.
- Improves transcription and caption accuracy.
- Makes people sound like they're in the room, not on a phone.
Where the bandwidth gets set
Audio quality on a call is limited by the weakest link:
- The microphone and speaker. Their frequency response must cover the band.
- The device's USB or Bluetooth link. USB carries wideband and better easily. Bluetooth headset profiles used for calls may be narrowband or wideband depending on the device and computer; a USB dongle often gives the best result.
- The meeting app's codec. Teams, Zoom and Google Meet all use wideband or better codecs between computers and room systems.
- The other end. Someone dialing in from a phone line brings the call down to narrowband for their audio only.
Higher sample rates use slightly more network bandwidth, but voice audio is tiny compared to video. See video conferencing bandwidth.
Frequency response vs sample rate
Spec sheets often list frequency response (for example, 100 Hz - 20 kHz for a speaker) rather than sample rate. Frequency response tells you what the hardware can reproduce or pick up. For voice calls, look for microphones that reach at least 7 kHz (wideband) and ideally 14-16 kHz.
What to look for when buying
- "Wideband", "super-wideband" or "HD voice" in the audio specs.
- Mic frequency response that extends to 7 kHz or higher.
- A USB connection or included USB dongle for wireless speakerphones.
- Full-duplex audio so both sides can talk at once.
Catalog examples with listed audio bandwidth
| Device | Listed spec |
|---|---|
| Jabra Speak2 75 | Super-wideband up to 16,000 Hz |
| Jabra Speak2 55 | Wideband up to 8,000 Hz |
| AVer FONE540 | Wideband, full duplex |
| Poly Sync 60 | Dual 50 mm speakers, 75 Hz - 20 kHz |
| Yealink CM20 | Mic frequency response 120 Hz - 16 kHz |
| Logitech Rally Mic Pod | Mic frequency response 90 Hz - 16 kHz |
Compare devices in best speakerphones and how to choose a speakerphone.
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