I'm have industrial deafness and when I hear boofheads playing their doof doof music??? that sounds so loud to hearing impaired me and my car doors are flexing from the vibes it royally p****s me off.
If your music's playing loud enough that you can't hear a police/ambulance/fire engine siren then it's too loud. That can be considered (by a police looking for any excuse) as driving without due care and attention. Does that make loud music illegal (or unlawful)?
I sometimes wonder if the older generation (I use this term with the greatest respect ) had the kind of audio power & quality that we (Slightly younger people) enjoy now while listening to their favourite bands; Beetles, and other such like groups, would they still view some of the music today and the volumes they are listened to as being to loud? Food for thought