It may be caused by interference. Try putting a sheet of aluminium foil between any electronics that are stacked on top of each other (like your satellite receiver box, DVD player and games console).
Only wash clothes when you absolutely have to. Did you know that the best way to freshen up denim, gym wear or fluffy jumpers is to pop them into a bag and freeze them? This gets rid of bacteria and therefore any stale smells without damaging the fibres! Good for killing moth larvae too!