I agree it probably isn't a big deal, but at the same time if it is really driving you crazy, if you don't resolve it one day you will go off and cause a big scene and make a jacka$$ out of yourself, so it is better to deal with it now. I'm sure there are ways you can approach the subject without ruffling his feathers, but also letting him know. I mean it is quite possible he doesn't even know you can hear him especially if it is his first job in a cubicle and he may not want to be that guy that annoys his cube mates.