I've just swapped my old 07 plate Smax for an identical 63plate model. The stereo system in the new car is a 6000cd with bluetooth and voice control. in my old car I had my iPOD classic connected through the 30 pin dock connector into the aux input and it played well. When I connected this to my new car, the sound quality was awful. I took it back to Bristol St and they said there was no fault. I discovered that they connected it through the headphone socket on the iPOD and that plays fine. I have two iPODs and two leads, which all play well in other vehicles, so there is no issue with the players or cables that I can see.

I've tried it on several other fords with the same radio and there is no issue. I can only assume that there is a fault with the aux cable from the centre console or the radio unit itself?

Any thoughts on this issue?

Curious - my guess is some weired grounding issue. Do you charge your Ipod when listening in the car (and does disconnecting power make a difference)?

When I was looking to purchase a Bluetooth audio receiver that would connect to aux in in my cd6000, I went after the recommendation I've found online and bought a ground loop isolator to go with it, one of these: https://www.amazon.co.uk/dp/B01LYYRT7M?psc=1

I have to say that it has eliminated any strange buzzing and noises. Perhaps it would help you, too. It's rather small (looks much bigger on a photograph). Worth a try?