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Hagia_Sophia_InsideOften here we speak of the details of worship, altar placement, the motions of the clergy, the hymnology, and much more. We often, many of us, decry the modern sanctuary, as austere, even brutal. Well, I won’t argue that because I’m one who says that. We lose something of the awesome that we get in the older churches, especially the medieval and earlier cathedrals.

But there is something else as well, how do those churches sound? I’ve down some work over the years on sound systems, and I have done a few home theaters. What we try to do in those is to make the space neutral, so that the electronics can transport us pretty much anywhere, from the rim of the Grand Canyon to a New York City broom closet. It’s a lot more technical than you think to do that. There’s lots of knowledge, and math involved, not to mention computer simulation if one is to do a good job.

That true on the other side, as well. You may think that modern rock is simply noise, some of it I do as well, but I’ve been around enough to know that that noise is processed, even if from acoustic instruments, and vocals by multiple tens of thousands of dollars worth of equipment, and by very knowledgeable people. In fact, I just spent about $500 on my sound system, it’s all audio processing gear, my amplifiers and speakers are fairly OK for my space. Why, because with my computer involved, I can tailor it more exactly to my desire. Granted, I may be pickier than most, but it’s a matter of degree.

But about those old churches, well, if you’ve noticed, when I post music, it’s nearly always from the Mormon Tabernacle Choir, King’s College, Cambridge, Westminster Abbey, and lately Norwich Cathedral. Why, because for the same talent, they sound better in those spaces, which were designed for sacred music. A choir in a gymnasium almost always is muddy, with uncontrolled echoes and standing waves, sometimes to the point that the musicality is completely lost.

A while back Malcolm wrote (yes, I miss him too) about Hagia Sophia, and how even in its semi-state of disrepair, how awe inspiring he found it. That article is here. He’s right, of course, as his pictures show. But how did it sound? And does that enter into the worship as much as the visuals? Although here we are discussing Hagia Sophia in Thessaloniki, Greece, which is more or less a copy of the one in Istanbul

The Atlantic carried a story about that recently. What they found is that it makes a huge difference. Here’s a bit but you should read it all.

It wasn’t just about the architecture. They had these big jugs that were put up there to sip certain frequencies out of the air … They built diffusion, a way to break up the sound waves by putting striations in the walls. They were actively trying to tune the space.”

“They also discovered something that we call slap echo,” Donahue added, “when you have walls fairly close to one another and the frequencies go back and forth. It goes ta-ta-ta, ta-ta-ta, ta-ta-ta, ta-ta-ta,ta-ta-ta. [In the ancient world,] they described it as the sound of angels’ wings.”

When Donahue and his colleagues were in Hagia Sophia—once the cathedral of Thessaloniki——they used a test tone at different frequencies to see how the space responded to sound.* The tone ranged from about 50 hertz, which sounds like a low buzz, to 20 kilohertz, a high-pitched whine.  “I heard the standard sweep tone until it hit 6 kilohertz, and then it just spread out everywhere,” Donahue said. “I could hear the fluttering. I said, ‘Wow, those are the angels.’”

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.”

It really is, this is how the Byzantine chants were supposed to be heard, not in a barn. What an amazing project!

Far too often we consider those who came before us as semi-savages, they weren’t. In some ways, they were more advanced than we are. I don’t know of a modern acoustician who could do what was done in those churches, and we are the poorer for it.