Resonant Frequencies of a Room

I just came across the original recording of Alvin Lucier made in 1969, entitled "I Am Sitting in a Room." With it, he explores the resonant frequencies of a room by recording and re-recording himself as he delivers the following monologue:
"I am sitting in a room different from the one you are in now. I am recording the sound of my speaking voice and I am going to play it back into the room again and again until the resonant frequencies of the room reinforce themselves so that any semblance of my speech with perhaps the exception of rhythm, is destroyed. What you will hear, then, are the natural resonant frequencies of the room articulated by speech. I regard this activity not so much as a demonstration of a physical fact, but more as a way to smooth out any irregularities my speech might have."
The first measured delivery carries emotional weight, punctuated as it is by his occassional stuttering. The somewhat pained monologue gives way to the song of the room with each re-recording, in which imperfect Lucier becomes the perfect string vibrating with resonance to the soundboard of the space.
For me, listening to this was a spiritual experience as I reflected on my own speech in my own room, or for heaven's sake, the sound of singing in a cathedral and the way it all must sound to God.
To listen to Lucier's performance click here