# Lucier's "Resonant Frequencies"



## nau5ea

Having recently discovered the work of Alvin Lucier, I was wondering just how legitimate his claims of finding the "resonant frequencies of the room" by recording his voice over and over truly are. Is there science to back this up? Is it commonly held knowledge? Should I take this to a physics forum?

Thanks,
nau5ea


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## tortkis

If the room is not an anechoic chamber, sound would be reflected at the walls, and the reflected sound interferes with the sound directly heard from the source. For example, if you generate a sine wave sound, and the reflected sound wave has the opposite phase when it reaches at the source, the sound would be reduced. On the contrary, if the phase of the reflected sound corresponds with that of the original sound, it would be amplified. In case there are many objects in the room, the interference would become more complicated, depending on the size of the room, the materials of the walls and objects, their layout, temperature, humidity, etc.

The sound of speech contains various frequencies, whose spectrum is different for each person, some of which would be amplified, and some of which would be reduced. Therefore, if the spoken sound is fed back to a recorder again and again, the resonant frequencies of the room would be emphasized, thus the resulted sound waveform becomes unique to that room (and to the speaker.)


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## Heck148

As a performer, I've many times experienced "Room resonance" in different concert locations....

I've noticed it as a listener as well, tho not nearly as often...

one time I remember quite vividly - Barenboim/Chicago were performing Bruckner Sym #8 in Boston Sym Hall. I was sitting in the upper balcony, center section to the right side....the brass sonorities were cosmic, indeed - and I remember the tuba [Gene Pokorney] sounded forth a high F [f above middle C] that just jumped out of the sonic fabric - it really rang!! I thought the tuba was sitting right next to me!! It happened a couple of times during that performance...something unique about where I was sitting, where the tuba was placed, etc...


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## millionrainbows

I've made didjeridoos out of cardboard tubes. You hum or sing into them to find the resonant frequency.

When I set a PA system up, I turn it up until it feeds back. I figure out what pitch the feedback is, and back it off until the feedback subsides. It's all very musical. Resonant frequencies are a common occurence.

Frank Zappa had a parametric EQ filter built-in to his guitar, and each auditorium or room he'd play in, he'd tune-in to the resonant frequency with the filter, to increase his ability to play "feedback notes" with his guitar during solos.


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