Autism headphones or earmuffs are a must have in your ASD bag of tools! I use them anytime my child goes to a party or sporting event. Not only do they muffle the loud noises, they seem to allow my child effected with Autism to focus more.
Sometimes I catch my son holding his own ears when he is trying to concentrate. I just pop on a pair of the Califone Hush Buddies and he lets go of his ears and is much more comfortable. The Autism ear muffs don't cut out all of the noise, they just turn the volume down a little for our children that are sensitive to noise.