[ Okay, things we've learned: he's not a kaiju like the ones they've been fighting. That's good! And he's clearly amicable enough. Even better! Though as she stands next to him and watches him tear the stereo apart, Lucy's rifling through her memory for the proper names of the "organs" he's poking at. ]

I think that's called the motherboard. The "brain." It sends the signals to the rest of the parts to read the music and play it.

[ The one he found has a CD reader in it, which she points to before gesturing to the speakers next. ]

That thing will read music off of these disc things called CDs, and the sound will come out of these parts here.