The sound of the Hagia Sophia, more than 500 years ago | Hacker News Reader

The sound of the Hagia Sophia, more than 500 years ago

npr.org

330 pointsblegh86 comments

You can find some recordings of a live concert done using this technique on YouTube: https://www.youtube.com/watch?v=bHpOiX2sO-s

I've been learning and singing Byzantine chant for over a decade now. In fact, I ended up learning programming because I wanted to create software for Byzantine notation, which is very different from western notation. Here's an example of (modern) Byzantine notation with renditions in western notation: https://cappellaromana.org/wp-content/uploads/2014/04/Cherub...

The top line of western notation shows a fairly straightforward version, while the bottom line shows one fully-ornamented interpretation. Note that microtones are used. As far as I can understand, ornamentation/interpretation can vary by teacher, and I once found a paper that analyzed the microtones used by various famous chanters to see the differences between them.

I never did end up creating any useful open source software for Byzantine chant. I did learn Racket, then Django, then became a programmer and now I'm a data scientist. So I partially ended up where I am because I was sick of typing out Byzantine chant using special fonts in Microsoft Word! There are now actually a lot of symbols in unicode for Byzantine music, but I don't think there's any way to handle the typesetting necessary for combining neumes in the various possible ways yet (think of how Korean works)... but I haven't looked into this for a few years.

I love this music, not only for the beauty of its sound but also the incredible richness of the hymns. There are teachers in the United States working on developing good methods for teaching all of this to people without such a cultural background, and critically, singing it in English so that the meaning can be understood by those who don't know Greek or Arabic. Chanting with my choir is one of my greatest joys in life. Glory to God for all things.

I appreciate the links and your story sounds interesting. I’m an Orthodox catechumen myself and am very interested in learning to sing the Liturgy as well as other chants. Might you have any tips or resources on how one might start really learning (besides just practicing)?

Just show up to liturgy early and practice with the choir! They'll be happy you're there, and you don't have to sing during service if you aren't comfortable.

For Byzantine chant, I strongly recommend immersing yourself in the music by listening to it as much as possible. Try to focus on music in your native language--if it's English, then there are more and more recordings coming out. Become familiar with the scales that are used and learn what tone each song is going with. Memorize and sing back the simpler melodies that you can manage, such as the troparia commonly sung every week.

If your parish does chant, express your interest to the lead chanter and see what they have to say about learning. While we of course want everyone to be able to participate, if somebody is really off (especially with ison, which are the held "bass notes"), it can confuse people and cause a lot of chaos in the middle of a service. :)

If your parish doesn't chant (meaning they only sing perhaps Russian-style four-part harmony), then you have a more difficult road ahead. It's hard to develop this skill without a mentor and without often practicing it in the real life context of the services. And it's of course nice when you don't have to lead a service while also being a beginner!

I encourage you to check out https://www.byzantinebeginnings.com/ It's a unique teaching method for chant using games and exercises, rather than just reading sheet music. Although I had chanted for many years, after I took the first course I really improved a lot. A good friend of mine is involved in creating it and has used her professional teaching experience to shape its pedagogy, although it's still being refined between sessions.

Finally, I strongly recommend learning Byzantine notation over using western notation, even if you are familiar with the latter. Byzantine notation is a DSL optimized for conveying the subtle rhythm and ornamentation that is often lost in translations to the western staff. The loss of this can make renditions sound stale and lifeless. As you can see in my original comment, fully translating such nuances results in way too much boilerplate! An experienced chanter can read a series of neumes like words in a sentence and know all of the musical richness to impart to it.

May you have a blessed start to your Lenten journey.

Thanks so much.

I sang on this CD. The NPR piece linked here appears to be based on a segment we did a few years later for Pop-Up Magazine in Oakland. An interesting technological tidbit that they didn't mention is the use of contact mics for recreating the Hagia Sophia acoustic in live performances (and the CD recording). The Stanford crew would tape these tiny mics to the middle of our foreheads (with wires running down to portable wireless transmitters on the belt) to get a good mixable channel for each singer, which would go through their signal processing gear to produce an acoustic backing mixed with the live singing. This is totally unusual for performances of this repertory; you normally do concerts entirely "acoustic" with no mics or monitors, and good recordings typically involve either a single pair of crossed mics in front of the whole ensemble or a few strategically placed mics in the space, but no per-singer channels and pop-style mixing tech.

The next step (that will probably never happen) would be to refurnish the Hagia Sophia, as it would have been before it was plundered in the fourth crusade, and seat an audience in it, as if for a mass. Then pop another balloon. All those extra furnishings and bodies would have had a significant impact on how the space sounded. The plastered over mosaics might also create a noticeable effect that would need to be compensated for. Even with the impressive work of Abel and Pentcheva we still have something that would likely sound empty and strangely hollow to people familiar with the Hagia Sophia when it was serving as a church.

The last Orthodox church services were in 1453. So I doubt that there will be many critics who remember back that far :)

Some Greek chanters got permission to go into the Hagia Sophia and record a TV special (for Greek TV) of chant music several years ago. While not a service, it is the music that would have been used at a service. (Either that, or this is another case of convolution reverb and some clever video editing. I'm not sure. But it sounds pretty cool.)

Part of it: https://www.youtube.com/watch?v=e1aUZcHaJb4

Another: https://www.youtube.com/watch?v=-eCZyvczZaM&t=98

Actually, there was an (incredibly unauthorized) service held in 1919 during the Allied occupation of the city:

https://greece.greekreporter.com/2019/09/26/the-brave-greek-...

What an amazing story! Thanks for sharing that.

Great story.

That could have turned out so much worse for all involved, but I suspect those involved had different perceptions of the risks than we do now. Though there was still some risk of dying, this must have seemed like a cakewalk compared to jumping out of a WWI trench!

"All those extra furnishings"

I don't know that there would be extra furnishings. It's not unheard of for Orthodox churches to only have seating around the perimeter for the sick and elderly. It's common for worshipers to stand during an Orthodox mass.

I find it strange that people and historians are so fixated on the 4th Crusade as the be all end all of the Byzantine's and ignore or minimize as much as possible all that irrelevant side business of the centuries of fighting with the Muslims. You know, the guys that fought them far more often and more brutally and actually took away nearly all their territory and destroyed them? In addition to the above comment and a few others in this thread take this video for example.

https://youtu.be/Okph9wt8I0A

It's totally done on a politically oriented ground to denigrate a religion and culture, and put another in favouring light. If people were more educated about some historical facts (for instance the bloody conquest of India) it would be harder for some people to keep the power and push their agenda.

Don't forget the Persians before the Muslims or all the self-inflicted damage from coups, inept emperors, etc..

In this case though, the fourth crusade really is important since it was when the Hagia Sophia was first looted during a sack of the city. Nearly seven centuries of accumulated treasures were carted out of the place.

You don't have to measure it, strictly speaking. When you know the acoustic material properties of the surfaces well enough, you can compute an impulse response with high enough accuracy (getting to one jnd and below). The tricky part is knowing the material properties. These are often just guesses as measuring them in situ is very difficult/impossible.

I don't know about it feeling empty and strangely hollow. I've sung in plenty of very large cathedral spaces, and even when they're packed with people they're still immensely resonant, sometimes to the detriment of the music - singers often prefer smaller spaces where the sound doesn't get lost in an acoustic bathtub. And as another commenter pointed out, there never would have been rows of pews in the Hagia Sophia like in a western church.

> Now imagine - it's the early 13th century. You're sitting inside the Hagia Sophia. Marble pillars rise up around you. Dusty light filters into the windows in the massive dome above.

The Hagia Sophia was also a great tool for the Byzantine Emperors to convert other leaders to Orthodox Christianity. There are stories of various leaders being so overcome by the experience of a mass in the Hagia Sophia that they embraced Orthodox Christianity and became allies of the emperor.

That basically works like the concept of "culture" in the Civilization video games. If you have more "culture" you gain all sorts of upper hands over the other players.

(I know the comparison is rather silly)

Seems like a very apt comparison. The spread of Christianity and Islam, including denominational conversions, works much the same today. In fact, in some places it's far more crass--fancy cars and huge televisions replace grandiose public buildings and fine art as symbols and enticements of a more civilized and prosperous life awaiting converts.

I don't mean to demean religion, it's just the reality of how mass conversions often work. You get pulled in by the fancy cars, but you stay for the social networks and economic opportunities.

This was beautiful to listen to. By pure luck (should have done more reading), I was visiting Pisa in Italy. There's a building (the baptistry) _beside_ the leaning tower, which has the most perfect acoustics.

Every hour, they close the doors and a person sings a series of individual notes which then interact just _beautifully_ in the building. Hard to describe. There's a soundcloud[1] here, not mine, stars properly around 1:23. I think you really have to be there though, it was wonderful.

[1] https://soundcloud.com/miguelisazam/pisa-baptistry-of-st-joh... [2] https://en.wikipedia.org/wiki/Pisa_Baptistery

If you're interested, researchers from the University of Bologna have been working on virtual acoustic models of that space in its current form [0] as well as past configurations [1] that you might be able to look into. It is truly huge reverberation! And thus, pretty difficult to simulate.

[0] https://doi.org/10.1080/19401493.2020.1728382 [1] http://pub.dega-akustik.de/ICA2019/data/articles/000682.pdf

Just listening to the balloon pop in the Hagia Sophia was amazing to hear. Are there any other structures with similar acoustics that still holds performances?

Also there's a YouTube playlist of the recording they mention at the end, the Lost Voices of Hagia Sophia:

https://www.youtube.com/watch?v=-VrJ8XOwJzw&list=OLAK5uy_k98...

I don't know if it qualifies as a structure since it's open, but the ancient theatre of Epidaurus is renowned for its acoustics and is still operational to this day.

https://en.wikipedia.org/wiki/Ancient_Theatre_of_Epidaurus

Convolution reverbs are pretty cool. For Ableton Live Suite users, Ableton has made available a MaxForLive device that lets you make your own impulse response files for use with their convolution reverb, I've used it.

Howto: https://www.ableton.com/en/blog/make-your-own-impulse-respon...

Yeah... And some still remember recording the sound of popped baloons in different environments (or checked the response of analog filters to a single spike) to use it with first version of SIR VST. Awesome experience, at least as for that forgotten times.

This was really cool. It kind of clashes as I suspect the kind of people that like to hear cathedral music might not be into the lack of authenticity a filter added to a studio performance might give off. It would be cool to hear an actual performance side by side and see how close they got but that seems even less likely given the current politics.

Talked about in the bit, the Hagia was a church, then a mosque and is now a museum which is apt considering how many cultures touched this thing. This was mainly due to Ataturk's forward-thinking secular reforms in the 1930s. The current Turkish President Tayyip Erdogan has signaled his intention, multiple times, to change it's status back to that of a mosque[0] which I think rather unfortunate. Muslim prayers have been allowed at the site for a few years and I suspect it isn't long before Erdogan makes good on his promise.

[0]: https://en.wikipedia.org/wiki/Hagia_Sophia#cite_ref-67

A few years ago I went to Aya Sofya with a Turkish violinist friend who studiest at a conservatory here. Unexpectedly, up on the top floor, he pulled out his violin and started playing an Armenian/Azeri song called "Laz".

He made it through 3 glorious minutes before security escorted him out. The sound was unreal.

I would love to hear the same test done in the Basilica Cistern.

Do you have video?

Sadly / happily, no. The moment was too special to record.

My apologies, the song itself is called Lachin, not Laz.

https://www.youtube.com/watch?v=jq2KWVrLKEM

(Not the Aya Sofya moment)

The album of Capella Romana is on Spotify for whoever's interested: https://open.spotify.com/album/5iB2tDdXCTaV2PMlcgNYdA?si=X_k...

This will be my background music for weeks now :D

Here's the Apple Music link as well: https://music.apple.com/us/album/lost-voices-of-hagia-sophia...

And on Youtube Music

https://music.youtube.com/playlist?list=OLAK5uy_kFvQRadRiMgs...

Really beautiful, glad I took the few minutes to listen.

Couldn't agree more. For those who listened, Capella Romana's "The Lost Voices of Hagia Sophia" is also available on Spotify. It's amazing.

You might like to listen to https://en.wikipedia.org/wiki/Gregorian_chant

Digital reverb algorithms are a huge and interesting area. One can recreate the acoustics of a venue from recordings of a balloon pop or a pistol shot. One can also create physically impossible reverbs, where the echoes precede the actual sound or get louder instead of fading.

Could you point me to more info/examples on physically impossible reverbs?

Convolutional reverb means you convolve the impulse response of a system with a "dry" input signal to get your output. If the impulse response has any content before t=0, that content will cause a sound in your input signal to have an effect on the output before it happens. "Acausal" is the jargon.

that's possible with normal reverbs too. reverse reverb is quite a popular creative tool. i've used it on snares to make them suck you in before popping you out

The "Unnatural" section here covers a few varieties of unnatural reverb effect [0]. (I'd also recommend many of the items with the "theory" tag on this blog)

In addition to those, reverbs that modulate the pitch signal are very common in music, but are physically impossible on a large scale. Most are subtle and create a detuned "thickening" sort of sound. Some will change the pitch by a whole octave or more. [1]

Artificial reverbs can also have their decay rates adjusted dynamically, and can even decay "negatively" so that the reverb actually grows in volume. Any other parameter could also be adjusted in real-time (depending on the reverb) [2]

[0] https://valhalladsp.com/2018/05/14/effect-o-pedia-reverb-typ...

[1] https://www.youtube.com/watch?v=wlwdmxuBuyM "The Black Keys-The Go Getter"

[2] https://www.youtube.com/watch?v=OJDW9l2cw0I&t=60s Make Noise Erbe Verb reverb module

Beautifully done, especially the transition from the studio to the simulated environment.

You can hear similar choral music if you visit an Orthodox Church or monastery, specifically a Greek or Georgian one maybe.

It says on Cappella Romana's site that "For a thousand years, Hagia Sophia was the largest enclosed space in the world."

An interesting fact to get out this rabbit hole.

I remember the first time I saw a drawing of Hagia Sophia in my history book. I was so amazed! It baffles me that the designers and builders of these “ancient” marvels often did not know why, from a scientific standpoint, that these buildings didn’t just topple over.

This sound bite is magical.

Truly beautiful, thanks for sharing.

Kind of reminds me of the following bit where deadmau5 talks about reverb and compression to create a sound that goes beyond what the oscillators generate. He plays a tune without, it illustrates a similar effect. (warning: lots of cussing)

https://www.youtube.com/watch?v=vYr6nlqV3oA&feature=youtu.be...

This practice continues in the Armenian church in their liturgical music: https://www.youtube.com/watch?v=JmQcQ4M8ROg&t=740s

Not coincidentally, Armenian church and its rituals are some of the oldest in the world.

Not to 'akshually', but this specific practice more directly continues in the greek orthodox church - greek & armenian churches began to split in 500s before hagia sophia was completed and split was 'complete' shortly afterwords, which is not to say there are not many similarities.

Sad that we don't really consider acoustics when building our modern structures/dwellings these days.

We do when building halls/stadiums/opera houses/temples/places where acoustics matter.

I think Parent suggests that acoustics matter more than just in spaces for explicit sound consumption.

Yes like open office plans.

Any links or ideas on what it would sound like during the Ottoman Era? It was the primary mosque of the empire for centuries, so I’d imagine there had to be some form of singing or chanting (Sufis, maybe?)

On a related note, I've just finished Istanbul - A Tale of Three Cities by Bettany Hughes - which covers the amazing history of the city, strongly recommended!

tl;dr: analyzing the sound of a balloon popping in Hagia Sophia, they made an audio filter using techniques and understanding of sound in space that only became available in last 10 years. Cappella Romana made an album called Lost Voices of Hagia Sophia using this filter to recreate the experience of listening to Christian chants in that space. It's available on Spotify, headphones probably best.

So it's like they sent a dirac spike in the real thing and managed to capture the full response? If so, very neat!

> they made an audio filter using techniques and understanding of sound in space that only became available in last 10 years.

This is an old technique. The idea of convolving the impulse response of a system with an input to yield the output is the basis of LTI systems theory. And while convolution isn't the most computationally light operation in the world, computers have been up to the task of practically performing such operations on audio signals for at least 20 years.

There's been some more recent work about more efficiently and accurately measuring the impulse responses of a space, but given they're using balloon pops, they're not using that work.

Offline audio-rate convolution (particularly with shorter impulse responses) has been plausible for a while, but real-time convolution reverb has definitely come into its own over the last ten or fifteen years. Overlap-adding blocks of audio that have been processed in the frequency domain with a low enough latency so as to feel instantaneous is a more recent capability that likely had an influence on this work.

I think the reason they used balloon pops was because that was all they were allowed to use: many heritage or archaeological sites can be nervous about researchers bringing in large loudspeakers and amplifiers, whereas a portable recorder and a bag of balloons can feel a little more harmless. Most acoustics researchers are aware of and use those new techniques whenever it's possible!

I wonder why one would need an impulse response recording. The dimensions and materials of the chamber are known. Seems like the effect could be synthesized from that.

As I metioned earlier, the tricky part is measuring the materials. The rest can be done with pretty high accuracy. There are commercial packages for that like Odeon or CATT acoustics.

These days, some of the simulation algorithms are slowly trickling into game engines, too, with the push for realistic VR. Unfortunately, these still require some larger quality/performance tradeoffs because they have to share the processor with all the other work the engine has to perform. But it is still quite convincing. So with this tech, you actually get to walk around in a space and hear the reverb adjusting in real time, even when the geometry of the space changes.

Impulse responses (or an equivalent like transfer functions) are the ultimate output of such a model. Here, they're measuring them directly.

This sounds very much like modern day Georgian choir singing.

O man I heard this on the radio and it gave me chills.

Instagram filters for sound. You heard it here first!

have they made the impulse response data available. would be great to load this into Logic Pro X to use on other material.

do the acoustics of the Hagia Sophia differ from that of the Pantheon/Basilica of St. Mary and the Martyrs in Rome?

TLDR; they took an impulse response in the building for use in a convolution reverb.

https://en.wikipedia.org/wiki/Convolution_reverb

Truly magical!

"Only possible in the last 10 years" is not correct.

Computer musicians have used the IRCAM ISPW board as far back as 1989 to implement live real time convolution. Single purpose realtime convolution reverb hardware has been commercially available since Sony's 1999 DRE S777. Non-real time convolution has been done for decades as well, including by myself in 1991 and likely hundreds of others during that time period. Real time convolution on an off the shelf affordable consumer platform has been available for a long time as well, including eMagic's Space Designer plugin which was released in 2003. It's still part of Apple Logic.

I think Abel was talking about his and his colleagues work in this paper when he said the 10 years comment: https://www.researchgate.net/profile/Bissera_Pentcheva/publi...

He's not just talking about being able to do convolution.

To be perfectly clear, some have been sampling reverb spaces for use in convolution reverbs using a starter pistol since the 1980s, and the procedure became widespread in the 1990s.

It is not 10 years old at all in any imaginable interpretation.

This person's "innovation" of popping balloons instead of using a starter pistol is completely and totally irrelevant and inconsequential.

Right. I'm curious what the recent advance is. "Pop a balloon to get the impulse response and use that to build a linear filter" was well known when I was doing signal processing work in the very early 2000's.

My reaction to '10 years' also. I recall using some (forgotten, Mac) inpulse conv in the early 2000s. (Not real-time!) This SOS article links many reviews dating back to 2002-04 (the earliest for the Audio Ease 'Altiverb'). https://web.archive.org/web/20161209164745/http://www.soundo...

I find chants very relaxing. And, it has nothing to do with a specific religion.

P.S. Its weird, but the Orthodox, generally speaking, "hate" Catholics more than they hate Muslims. In fact, a Muslim was /is the referee to the Church of the Holy Sepulchre https://www.reuters.com/article/us-religion-jerusalem-church... Might have to do with the split and a tiny thing like https://en.wikipedia.org/wiki/Sack_of_Constantinople

>In fact, a Muslim was /is the referee to the Church of the Holy Sepulchre

The Catholic Church has partial jurisdiction and would also be subject to any referee-ing.

> Might have to do with the split

Probably has more to do with holy lands having being british territory prior to the creation of modern israel and the uk/jordanian relationship - similar arrangments exist for other disputed holy sites in the area

Context for the sack: https://en.m.wikipedia.org/wiki/Massacre_of_the_Latins

As witnessed with the Ukraine/Russian split, the Orthodoxy doesn't even like each other. The Orthodox Churches have historically been Catholocism's strongest political/military opponent.

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