Two stories below Broadway, beneath the ceaseless hustle and/or bustle, there's a ballroom in the belly of the Los Angeles Theatre. When it's an empty belly, everything echoes, as though calling forth the sounds of past dancers up from the bedrock and delivering them once more. It's the kind of rippling acoustic reverie that sounds like laughter, or ball bearings, or birdsong, depending on where you are in the room. It's not something that gets mentioned much on the L.A. Conservancy's walking tours, and seldom do those Sunday tours make it all the way down there — but when they do, the sounds that come pinging and ringing from the footsteps of the curious are enough to make one's pace slow in order to feel the effects of each foot fall. What results is a joyous pause that recalls the first time you ever heard your own movements create a weird sound. The best listening spot is at the center of the room, where the wood bends and yaws just enough to make the sound that much more pronounced — a wet, bouncing kind of reverb and echo created by more than 75 years of people enjoying movies and, on their way to the show, creating another kind of spectacular in the process.