No audio, crackling sound from speakers.

MrZapie

Hi,
Help what's happening here to her indoors (wife in the US) 2010 roadster;

Driving along audio on, speakers start to crackle - noises similar to sparking or shorting out and very loud and quite alarming to the extent my wife got out of the car expecting it to turn into a mobile BBQ.

Speakers still make the same crackling sparking noise with audio and screen off.
Shutting the car down will sometimes sort the problem but invariably on a restart there is no audio, radio and media play but no sound from the speakers.

I'm guessing it may be a poor earth (ground) somewhere - does the roadster have a separate amplifier?

Any help greatly appreciated - Thanks in anticipation