Not being averse to a little experimentation I decided to 'fix' the problem of taxi-driver RF interference on the pc sound system...so I lined the sub-woofer box, which also contained the active electronics/psu, with aluminium foil.

Now when I put this all back togeter and tested it with my mobile phone (good source of RFinterfrence) it worked marvelously, but a little later, somehow the circuitboard or psu or something, got shorted out buy the foil...bye-bye (big-style) speaker system