Sorry if this has been asked before although I did do a search and found nothing: I have an active subwoofer (Teac) and every time the washing mahine, tumble dryer or central heating pump switches on or off I hear a loud "thump" coming through the sub. This is oviously a mains spike that the sub can't deal with. Has anyone else experienced this, and have you found a solution e.g. an in-line filter etc. Thanks.