The Bluetooth RF transceiver (or physical layer) operates in the unlicensed ISM band centered at 2.4 gigahertz (the same range of frequencies used by microwaves and Wi-Fi).

How does it work? To understand how a Bluetooth connection works, we need an example of the wireless technology being used, so let’s take a phone connected to wireless speaker.

Make sure you use wired speakers or headphones; don't add an additional level of Bluetooth to the test. More audio recommendations Best wireless earbuds and Bluetooth headphones for phone calls ...