The members of Metallica do not exactly do a whole lot of solo-acoustic shows; they are, after all, in Metallica. But last night at the Fillmore in San Francisco, James Hetfield played a quick unplugged set. He and Sammy Hagar were co-headlining a benefit for the pediatric cancer program at UCSF Benioff Children’s Hospital. And during his performance — for what, as far as we can tell, was the first time ever — Hetfield turned Metallica’s Kill ‘Em All nugget “Motorbreath,” into an acoustic ramble. (Hetfield has played the annual benefit twice before, but in previous performances, he’s shied away from Metallica’s thrash-metal past.) Given that “Motorbreath” was never one of the quieter Metallica songs, this feels like a real accomplishment. Watch a fan-made video of the performance below.

But why was there so much crowd noise during the performance? Who talks through that? Hagar fans?