I currently have an issue with my B7 A4 Avant whereby the speakers will crackle intermittently. It's not caused by anything specific eg; bumpy roads or cornering etc, just as and when it feels like it. It's been getting progressively worse over the last week or two to the point this morning that the system would crackle, then blast out on top note, then go quiet for a few seconds before slowly returning to normal.
I had the head unit out yesterday and checked all the connections behind there and all is OK as far as I can see. I've also checked the connections on the amp and sub speaker in the boot and again, all appears to be OK. I've yet to disconnect the amp and just power up the HU to see if this makes any difference.
It's a completely standard OEM install. I've tried searching but it's not bring up much (maybe that's just me!)