Air horn! Air horn! haha, just kidding. But with my air horn experience, the longer and larger the trumpets are, the deeper the note. So if you can find an electric trumpet style horn, get the biggest trumpet you can...
I kept my stock horn on the steering wheel for polite beeps and added a hornblasters 4 trumpet air horn on a toggle switch to scare the sh!t out of people. It's too fun...
