Louder horns

I won a Hadley in a church raffle years ago. Tried to get a hundred bucks for it but didn't try very hard. Sat in my basement for years. After being cut off several times last summer for towing 60mph in a 70, I remembered I had it and mounted the horns facing down near the existing one on the passenger side. Now I get their attention when they pass me and rudely swing into my lane without leaving me any buffer. Very satisfying.