Do they distinguish between speakers and headphones/earbuds? In CA, the
law specifically says "a headset covering, or earplugs in, both ears":
27400. A person operating a motor vehicle or bicycle may not wear a headset covering, or earplugs in, both ears. This prohibition does not apply to any of the following:
So I think "speakers" mounted in the helmet are legal. PA's
law says:
§ 3314. Prohibiting use of hearing impairment devices.
(a) General rule.--No driver shall operate a vehicle while wearing or using one or more headphones or earphones.
Kind of similar. Maybe you could get away with a pair of mounted speakers