Why are phone calls such bad quality when something like a radio presenters voice is so clear?

Question

Why are phone calls such bad quality when something like a radio presenters voice is so clear?

In:

Answer 1

Bandwidth is one issue other have brought up but another big one is your microphone and environment.

Your phone microphone is just not that good. It can’t be, it has to fit in your phone. A professional microphone like what the radio presenter is using is large than your whole phone by like a factor of 10. It also has a pop filter a sound bored and mixer connected.

The radio presenter also isn’t in some random room. They are in a room that has been designed to make them sound good. At a minimum were are talking foam sound absorbents to stop sound refection, and outside noise. The room is often a special shape as well.