User blog comment:Godisme/Seven Dragons/@comment-175.136.146.106-20130501034810/@comment-7418318-20130501083526

Even if he has his sound powers I doubt they will be of much help. Not even Makarov and Jura were able to so much as scratch the Dragons, so Dragon Slayer magic seems to be the only option.

Of course it would still help in so far that it counters his weakness to very loud noises, but I don't see it working offensively against the Dragons.