Bluetooth LE which most smartphones support today is quite a bit different from Bluetooth classic. It typically runs at 1 or 2 Mbps and can trade bandwidth for error correction to get some impressive range. For example, this guy got 1.6 miles at 8dbm transmission power. https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/pos...

The audio codec on ble is more modern too.

> “You can't even hear a ok quality music further than 20 metres away” That smells like the SBC codec running on Bluetooth classic to me. Very different tech.