Very important... any advice?

My horse is not spooky at all, with anything that he sees. When he hears something on the other hand he gets very nervous. I realllllllyyyyyyy want to eventually rodeo with him but I am afraid all the music, clapping, and shouting will freak him out. Do you guys know any way to desensitize him to sounds, or any websites that can? I mean I know its possible or else there would be no rodeos haha PLEASE HELP THIS IS REALLY IMPORTANT TO ME!!! Thanks SOOO much in advance!!! :)