Help me find this audio experiment.

October 5, 2008 3:17 AM

I read about and heard an experiment about acoustic resonance. A guy made a tape in a room of his voice, then made many generations of recordings of the original recording. At the end all that was left on tape were the fundamental frequencies of the room. I can't find it anywhere. Ring any bells?
posted by TheCoug to media & arts (14 comments total)

I think you're looking for Alvin Lucier's I Am Sitting in a Room.
posted by bunnytricks at 3:27 AM on October 5, 2008

Is it Alvin Lucier's I Am Sitting in a Room?
posted by misteraitch at 3:28 AM on October 5, 2008

You can download the original 1969 recording at Ubuweb.
posted by jack_mo at 3:37 AM on October 5, 2008

Paul Morley talks about that piece a lot in his book Words And Music, which then partially influnced Strictly Kev (aka DJ Food) to make the megamix Raiding The 20th Century, which features I Am Sitting In A Room. He then made another version with Paul Morley contributing excerpts from his book. WFMU have it linked up here.
posted by Magnakai at 5:03 AM on October 5, 2008

Actually, it seems I've got the details slightly incorrect. Apologies.
posted by Magnakai at 5:05 AM on October 5, 2008

Bingo! Thanks all!
posted by TheCoug at 5:37 AM on October 5, 2008

For those in NYC, Alvin Lucier will be performing "I Am Sitting in a Room" *live* at Columbia University's Miller Theater on Friday, Feb. 13th.
posted by fourcheesemac at 8:52 AM on October 5, 2008

Oh my god that's creepy-cool. It's also freaking out my cat.
posted by notsnot at 8:59 AM on October 5, 2008

I imagine the frequency/phase response of the microphone, speakers, and recording device, along with the physical placement of microphone and speaker, has as much (or more) effect on the final result than any room resonances. The feedback sound in the later generations definitely sounds like it would be different if the speaker was rotated 90 degrees.

This could be tested pretty easily of course with a few simple experiments: tape deck vs digital recorder, omni mic vs cardiod mic, tiny speaker vs hi-fi speaker, etc.
posted by todbot at 1:45 PM on October 5, 2008

My memory's a little hazy (it's been 12 years since this lecture) but I recall Amar Bose telling us in class that he repeated this experiment with a speaker shaped like an eighth of a sphere in the corner of a room, to get more pure room modes. todbot, it's definitely true that you're recording the modes of the entire combined system (speaker -> room -> mic) -- you could, for example, place the mic at the node of a room mode that you wanted to exclude from the final mix.

On the other hand, for the most part speaker and mic designers try hard to eliminate serious resonant frequencies from their devices, so I'd guess the room modes are going to dominate. It turns into a really lovely demonstration of Fourier decomposition -- the original complex sound ends up represented by the discrete (infinite) set of room modes.
posted by range at 3:09 PM on October 5, 2008

Roll your own, I did it, it's fun.
posted by Area Control at 4:05 PM on October 5, 2008

For those in NYC, Alvin Lucier will be performing "I Am Sitting in a Room" *live* at Columbia University's Miller Theater on Friday, Feb. 13th.

What? what? Where? I can't find anything about this online -- how did you find out?
posted by suedehead at 7:44 PM on October 5, 2008

Hey -- it's not online yet. It will be. I am involved with the event. Watch the website (www.columbia.edu ) -- see the events calendar; it should be announced within a month or so, but it is definitely happening, Feb 13, 7 or 8PM, Miller Theater.
posted by fourcheesemac at 7:24 PM on October 8, 2008

Back with an update: the Columbia concert featuring Alvin Lucier has now been formally announced.
posted by fourcheesemac at 6:02 PM on January 12