STAFF PICK: These rooms are off limits to the public, but like all great wilderness, while most of us will probably never go there, just knowing it's there enriches our lives. It's like those recurring dreams of a little house with an infinite interior, the subconscious seat of all the music ever heard in Tucson. Up the grand staircase to the mezzanine, the chaos of the main floor becomes multiplied. Narrow pathways are cleared between boxes, piles of papers and musical instruments. But that is just the buffer zone. Go beyond, into the dim recesses, where every kind of musical instrument has its own special area: over here, a mountain of drums and drum parts, over there, a hill of trumpets as tall as a man. Everything gleams under a thick layer of dust and mystery. Go beyond again, down this little hidden stairway, through this tiny door. Duck under this threshold, and around the corner into a room the size of a basketball court, ordered with piles of instrument cases, guitar necks, typewriters, chunks of piano, violins. Back in the deepest darkest recesses everything smells of age, and the visitor wonders how all these cavernous rooms fit into this one little building. As in all wildernesses, you'd be a fool with a death wish to go without a guide; and the mice would devour your breadcrumbs so you'd never find your way out.