2005 DB9 annoying hissing from rear speakers

[mike-2txrc]

Hi, it's just started recently but the back speakers make a hissing noise no matter if there is sound on or not.

Anyone had this and what's the fix?

Thanks in advance,

[nn7man]

Its 21 years old, could be all sorts of stuff!

[8Tech]

Not sure what age would have to do with it but most likely an earthing issue although unusual to be just the rear and not all 4. Whirring or buzzing would most likely be the alternator, but a hiss on just the rear sounds like the amplifier.