The Evolution of hifi speakers
https://www.goodreads.com/topic/show/20812804-addicted-to-hifi-speakers-us-too-6-reasons-we-just-can-t-stop
Bluetooth is actually a radio or wi-fi engineering made for short variety info communications in the economic, Scientific and Professional medical (ISM) band. The frequency array is from two.402Ghz to two.480Ghz,