Review on Giveet Bluetooth V5.0 Receiver for Speaker: Wireless Portable Audio Adapter for Home Music Streaming, Car Stereo, 16H Battery, Dual Link by Renee Cook

There were a couple of wires that ended up making whining noises and eventually started losing one side of the stereo, so I switched to Bluetooth. I don't notice any audio issues when switching from a phone to a Rockford Fosgate 9 speaker. If you charge it while using it occasionally, you hear a whine, but unplugging and plugging it back in stopped it for me every time. The only complaint I would have would be if I didn't charge it, it never seems to last more than an hour or two of driving. Keep a spare micro USB charger handy and it shouldn't give you any problems.