HELP with buying a car AIR HORN ?

I want to put a AH in my car. What are the differences between the train horn, fire truk horn, and big rig horn? Which one is better for my car? I was going to by the grover air horn
And how big of a compressor will i need? DO i need a 12 volt compressor or can i use one from the house and somehow convert it to 12? PLEASE HELP

thanks