Roosters will crow. If there are no circumstances that encourage him to crow more than usual (mainly keeping multiple roos or keeping him separate from the flock) there is nothing you can or should do. No crow collars are cruel - guve him away to somewhere where he can behave like a normal rooster.
I suggest earplugs. Those collars don't stop crowing, the poor guys still try and it sounds like they are strangling, plus alot of them have bows on them so it looks like a tie.You end up with a rooster that looks like Peewee Herman and sounds like chain smoker.
Honestly, that's pretty much the truth of it. If you can't tolerate a rooster crowing, you probably shouldn't have a rooster. Rosters crow. It's what they do. Some are worse than others, but you have to expect it. Putting some sort of mechanical device on them to try and mute it just doesn't sit well with me. I like having a rooster around, but I do it accepting what comes with it. If I had reasons why one wasn't ideal I would (and have) run an all female flock. What are your reasons for keeping a roo? If you're wanting fertile eggs, there are other ways to get them. Just a thought.