http://wiki.answers.com/Q/A_horn_must_be_loud_enough_to_hear_within_how_many_feet"
200 ft
In Florida 200 feet
Press in horn button. If you hear the horn, your horn is working. If you do not hear anything, then something is wrong. Part it out or just scrap it.
If you can hear the relay click, it's not a fuse. It's either the circuit to the horn or the horn itself.
The English horn is 2 feet 7.5 inches
Try to operate the horn and listen for a click from the horn relay probably located under the hood. If you don't hear a click I would check out the horn switch contacts in the steering wheel. If you hear a click I would check for power at the horn using a test light. If you have power at the horn connection when horn switch is activated it is probably the horn itself that is bad. If you have no power at the horn connection when the horn switch is activated replace the horn relay.
HALF A MILE.
A Fog Horn.
You are operating a motorboat. You hear one prolonged blast from the horn of another vessel. What should you do?
The noise you hear is the horn relay clicking. The reason your horn does not work can be two things. Either you have a faulty horn, or you have a bad connection where the wire hooks to the horn.
Close Enough for Love - Shirley Horn album - was created in 1989.
Your car horn should be audible from around 200 to 400 feet away, depending on the specific design of the horn and the surrounding ambient noise levels. It's important for the horn to be loud enough to alert other drivers of your presence but not excessively loud to cause noise pollution.