K.L.
I took my little boy to a Monster Truck rally and used a combination of ear plugs and a hat that covered his ears. They make these earplugs made of wax and they form fit to the ear. You can find them at rite aid near the other ear plugs. I found mine next to the contact solution. I take one of the ear plugs and roll it up in my hands to warm it and make it plyable then split it in half and it is just the size for baby's ear.
hope this helps, and "Have Fun!"