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.