I added a Bluetooth transmitter to our stereo which broadcasts to a Sony Bluetooth speaker we place anywhere within 30 ft of out rig. Speaker has it's own volume control, and the transmitter just plugs into the earphone jack. Transmitter also charges off a USB port, so I just cable over to one of those. Works well and doesn't bother neighbors.
Note most radios that have "Bluetooth capability" can only receive, so adding a transmitter is required. https://www.amazon.com/Bluetooth-Tra...49784090&psc=1