Like a large fog horn. Deep notes and loud, super loud
the trains horn is very loud.
The sound of a horn can vary depending on the type and size of the horn. Generally, it is a loud and sharp noise that is created by air vibrating through the horn's hollow body. This sound is typically used to signal or alert others.
Super loud they have be that loud in case a a jerk in front of you is not paying atttenion.
horn
"klaxon"
the marching band was as loud as a train horn.
On average, a train horn is 110 db on the engine. At about 500 feet away from the train, a train horn is 90 db.
Loud.
loud
A foghorn is a loud horn used mainly by ships .
Legislation varies as to how load a horn may be. Check with your local authority