You’re on to something there. For all the little difficulties (what about those who are medically unable to shout? what about air horns?), the key goal that your plan has of increasing voter *interest* in participation, if it could be worked out, would be increased participation and more community spirit.
Here’s an idea to get your plan by some of the nay-sayers: do this at *every* major athletic event, all the time. If the incumbent doesn’t beat the challenger for the majority of events in any region or time period, the two have to meet for a grudge match — handicapping rules for physical abilities — match goes to the one who has the loudest fans.
If they don’t start booing their own, I’d put my money on Philadelphia, the town where they put this all together a few hundred years ago.