In reply to crayefish:
> Headphones?
I need to be able to hear the engine falling out.
> Any cheap 12V speakers (i.e. 12V transformer) can have the mains plug/transformer cut off and a cigarette lighter socket fitted to the end.
Another excellent solution.
> Though given vehicle electrics are actually 13.5V, not 12V, there is a small risk of breaking the speakers. But I guess that given they'd be cheap anyway, it's unlikely to be an issue.
Yup. Thanks.