Sunday, February 21, 2016

Ancient Acoustics

The Atlantic has a fascinating article on analyzing the acoustics of Byzantine churches:
The project began because Sharon Gerstel, an art history and archaeology professor at UCLA, realized something was missing from her already-deep understanding of Byzantine art. “What struck me was, we always look at paintings without thinking about the sonic accompaniments,” she told me. “So many paintings of a certain period contain representations of hymns and hymnographers, but people were looking at these paintings as if they were mute.”
The more Gerstel thought about it, the more this bothered her. The music of the Byzantine era, she decided, was a key to understanding her area of expertise—and not just the music itself, but understanding the experience of hearing it, and what it would have been like 700 years ago. “As an art historian, I could look at the pictures and say, ‘this is a nice painting of the hymn,’ but I couldn’t say anything about how the audience perceived that painting within a ritual setting.”
 They used some rather advanced technology to precisely map out the sound-profile of particular churches:
To map the acoustics of ancient spaces, to understand how a church was designed to reverberate at certain frequencies, Kyriakakis and Donahue gathered what’s called an impulse response. To do that, they placed loudspeakers omni-directionally throughout a church. Then, over the loudspeakers, they broadcast a test signal, like the one Donahue described in Hagia Sophia. “It’s a very long chirp that starts at low frequencies and goes up to high frequencies and it just sweeps through, like a whooooop,” Kyriakakis said. “And you record from various locations with microphones to see what happens to that chirp as it bounces around the church.”
The data showing what happened to the chirp in each part of the church is fed to a computer, which then registers the impulse response for the unique space. And here’s where it gets really interesting: Once you have a building’s impulse response, you can apply it to a recording captured in another space and make it sound as though that recording had taken place in the original building. 
“So you can take chanters with the original [Byzantine era] music and put them in a studio that has no acoustics,” Kyriakakis said. “They can sing a chant, and then we can process it ... and all of the sudden we have performances happening in medieval structures. It’s like time travel to me.”
I used to have a vinyl recording of the music of Giovanni Gabrieli recorded in the San Marco church in Venice--this was a big deal because his multi-choir and multi-ensemble music was specifically written to make use of the widely separated multiple choir stalls in that church. It is some of the most striking antiphonal music ever written.


 Being able to hear the original acoustic is almost a requirement for this music! But imagine how great it would be to have technology that could reproduce the original acoustic spaces of any music?

4 comments:

Anonymous said...

Reminds me of the phonautograph, which was never meant to play back sounds (but, rather, to train sound stenographers), but which now can. And so we have the oldest recording of a voice from 1860!

Bryan Townsend said...

Wow, I had never heard of the phonautograph!

Marc Puckett said...

Nor had I; very clever. I had what am pretty sure is that same Gabrieli recording-- all I can remember of it is the name E. Power Biggs, who was a famous organist forty years ago. Age, age....

Bryan Townsend said...

Yes, it was E. Power Biggs and a brass ensemble whose name I forget. Nowadays I imagine that no record company would be willing to accept the expenses of doing a recording like that--on location in Venice.