The picture changes dramatically when an external power source is connected. Since the battery does not last forever and needs to be recharged holds, I have connected the device with the included cables to the cigarette lighter. Immediately the sound image and a permantes background whistling and -brummen changes appear ... with the engine off, ignition only.
The same happens when connecting to a small radio device ... therefore I sent to Amazon back August MR220 unfortunately useless ... have the device