4G LTE Essentials

Real-world: Why VoLTE calls sound better than 3G

The Science Behind HD Voice

The dramatic difference in voice quality between 3G and VoLTE comes down to codec technology and frequency bandwidth. Traditional 3G calls use the AMR-NB (Adaptive Multi-Rate Narrowband) codec, which captures audio frequencies between 300 and 3400 Hz. VoLTE uses AMR-WB (Wideband), extending the range from 50 to 7000 Hz. This wider frequency band captures the higher harmonics of consonants like s and f, making speech sound natural and intelligible rather than muffled and distant.

Back to course

lab2 min

Lesson 26 of 33

Real-world: Why VoLTE calls sound better than 3G

Card 1 of 617%

Warm-up: Guess before you learn

Try these first, even if you're not sure. Guessing primes your brain.

A codec cuts everything above 3 kHz. How do "s" and "f" sound?

Both phones support HD, but calls sound narrowband. Why?

After narrowband and wideband voice, what comes next?

Answer all 3to continue — it's OK to be wrong.

All lessons in this level: