It's been more than 15 years since Hanson burst on the scene with "MMMBop."
Needless to say, they perform the hit song (and others) in a noticeably lower key nowadays than when Taylor and Isaac were teenagers and Zac was a little kid.
Check out them performing "MMMBop" live for Fifi and Jules in September:
The brothers can still harmonize, for sure. Think this would've been a hit if they were just releasing it now and you didn't know the catchy song yet?
For comparison, here's a live performance of the song from 1997: