They'll easily drown out anything outside, my only small niggle with them was they're less discreet than some of the proper beefy overhead jobs, ie other people can hear it when it's loud, but I suppose that the price you pay for having small light ones that you can wear with a helmet, it's a trade off I'm more than willing to make, up to you though.
For that price there they are sooooo worth it ^^^
Joe