Review on ZIOCOM Bluetooth 5.0 Receiver for Home Stereo: 3D Surround Sound, aptX Low Latency, Wireless Audio Adapter for Wired Speakers, Old Cars, and Home Music Streaming Stereo System (not compatible with TVs) - RC01 by Christopher Smith

This is the receiver you use to turn on the bluetooth on your old school wired speaker. It's a really simple process and it works great. This not only makes them Bluetooth but also adds 3D audio to them which sounds amazing I have to say. I love that this receiver automatically reconnects to the last device as soon as you turn it on. Of course, if you want a new device, you'll have to unplug it and fix it, but it's very easy to do.