If the noise also distracts him, the idea of an ear-net is nice. You can also use earplugs! But the most effective is to start of process of desensitization :)
Actually it is quite common that a horse is "afraid" or gets irritated when there are other horses. You have to desensitize him, you can do it by going for walks with other horses or by walking near another horse. You can also test the Equilibre Soundless ear-net, it will reduce the noises your horse hear!
It is fear? Or irritation? Try to get him used to be in contact with other horses, to desensitize him. Maybe he had a bad experience in the past, maybe a horse shoved him? Or maybe he jus want to play! If he is not aggressive with other horses, try to let him with some friends in a field so they can play and stay together.
Maybe you should try to speak to him? You could install vocal codes and use them when there are things that can distract him.