Whoa. Zac, the drummer for Hanson, is seven feet tall! Okay, not really. But when you crack the door to the studio where the teen-bro trio is jamming between recording sessions, the first thing you notice is that the pip-squeak is gone, his lanky ringer being a ponytailed, piccolo snare-popping Iron Giant. Only later, when they line up for a photo, will you realize Zac, now 14, remains an inch or two shorter than his older brothers and is still a baby-faced cutup, despite the impressive growth spurt. In any case, says Taylor, 16, “We do have a massive drummer.”