The radio bands are small. Each AM HD station uses 30 kHz which gives 40-60 kbit. That isn't enough for full fidelity music. And that is using more than one fre

The radio bands are small. Each AM HD station uses 30 kHz which gives 40-60 kbit. That isn't enough for full fidelity music. And that is using more than one frequency since analog AM is 10kHz stations. AM band uses a large frequency range, 530-1700 kHz, but the total bandwidth is small, slightly more than 1MHz. Telephone is bad compared to AM and really bad compared to FM or CDs. Human voice fits in much smaller bandwidth than music.