RickRob said:
So the police had a device that actually measured the number of decibels you were emitting? What was their evidence?
More importantly, what sound 'limit' is the OP supposed to have broken? There isn't one as far as I know for standard cars, it's all in the build EU regs.
I do get some quite unpleasant looking faces at mine in the country where said people assume that because my car is loud (it actually is quite loud with csl box and supersprint race box) I must be travelling faster than I am, whereas mister turbo diesel might well be travelling considerably faster just relatively silently. It's ignorance IMO and certainly an officer of the law should have no right to assume you have been behaving antisocially when he can't even see you. I would be contesting this personally.