Mapping the sound of Byzantine churches

To measure sound, you need to make some noise.

This story first aired in February, 2016.

Advances that have allowed us to physically hold 3D printed versions of lost artifacts, or to see 3D representations of ancient structures, have been huge advances in preserving our past. But having a full understanding of how people long ago experienced these objects and buildings goes beyond just seeing them, and how things sound is big part of how we experience our surroundings.

Sharon Gerstel is a Professor of Byzantine Art History and Archeology at UCLA. She spent years studying the art and ritual of churches from the 12th to 15th centuries, but she says that, "recently, let's say in the last 5 years, I've become interested in the sound aspects." 

Left to right: Nektarios Antoniou, UCLA professor Sharon Gerstel, the Rev. Spyridon Antoniou, USC professor Chris Kyriakakis, Jim Donahue, Konstantinos Raptis, Amy Papalexandrou. (UCLA)

As her interest in the actual sounds of these churches developed, a friend of hers showed her an article in the New York Times about a man named Chris Kyriakakis, who is the director of the Immersive Audio Laboratory in the University of Southern California.

The two of them got together and formed a team to travel to the Greek city of Thessaloniki (which also happens to be Kyriakakis' childhood home) to measure some of these Byzantine-era churches. They did this by setting up speakers and playing a sound pulse (called a "chirp") that, as Kyriakakis puts it, "...excites all of the audible frequencies of sound." 

They then record how the chirp sounds from different areas of the church, and using that information, they are able to capture the unique acoustic signature of the space.

But they didn't just record strange chirps. They also wanted to hear what could have actually been heard when these churches were built. So had music transcribed by Ioannis Arvanitis and Spyridon Antonopoulos from original Byzantine sources, and they brought in local chanters, Dimos Papatzalakis, Spyridon Antonopoulos, and Nektarios Antoniou, into the churches, and recorded the sounds.

"The Byzantines described the effect of the mingling of angelic and human voices," Gerstel told us. "So I kept joking, 'are we really recording what the angels sound like?' and I'm not kidding when I say it's almost exactly what it sounded like."

Using the audio signatures they gathered, they were also able to record chanters in a studio and make it sound like the chanters were inside one of these churches. Kyriakakis says he wants to use these audio signatures to create an "acoustic museum".

"When these structures in ten centuries from now, or next year, who knows... we could still for generations preserve what it was like to be in them through our ears. I want to collect as many of these impulses as possible so we can have this museum. That's my dream."