Yes, it's an award-winning piece of interactive installation art, but
we're keyboardists here: it's also the world's largest, fastest, most terrifying Leslie
rotary cabinet

Spatial Sounds
scans the space for visitors, then spins up to 100 km/h
in a circle, varying speed and direction. Understatement from the
artist: "Closer investigation
would be tempting fate, with the rotating arm swinging so powerfully
round . . . You can feel the displacement of air as the speaker whizzes
past you, and you had better step back, out of reach."
Indeed. The effect is apparently a bit more subtle than just a spinning
speaker, however: the artist and visitors describe an organic quality
to its movement as you move through space — i.e., sometimes it follows you. The effect of the interaction and the sound seems both scary and sublime.

Near Near Future got to actually check this thing out as the speaker terrorized local churchgoers.