7 ms·

Organ pipe physics

145 points by praash 3y ago

blahburn 3y ago
Would love to play around with this and hear the differences in sound. Something like what this guy did with the engine simulator https://www.youtube.com/watch?v=RKT-sKtR970 https://www.youtube.com/watch?v=RKT-sKtR970
- squarefoot 3y ago
  Interesting. I can totally see a similar software used to add combustion engines sounds to electric cars through hidden external speakers, possibly also as a service by manufacturers. edit: it appears to work well on Linux through WINE.
  - jacquesm 3y ago
    BMW already does this in their i8. It's complete crap.
mastazi 3y ago
Physical modelling has come a long way since it first appeared. Many of the instruments included in the Arturia V Collection (one of the most common collections of instrument plug ins) are made using physical modelling [1]. Modartt's products (even more so than Arturia) offer amazing control over the physical model, with the ability to configure per-note parameters [2]. Speaking of virtual pipe organs, for Organteq to compete with the market leader, Hauptwerk (which is sample-based) there needs to be a good choice of expansions though. With Hauptwerk, you can download hundreds of different organs from all around the world [3]. Modartt has an expansions marketplace for Pianoteq [4], why is the same thing not available for Organteq? [1] https://www.arturia.com/phi https://www.arturia.com/phi [2] https://www.modartt.com/pianoteq_pro https://www.modartt.com/pianoteq_pro [3] https://www.hauptwerk.com/instruments/ https://www.hauptwerk.com/instruments/ [4] https://www.modartt.com/pianoteq_instruments https://www.modartt.com/pianoteq_instruments
- Darthy 3y ago
  I don't think [4] is a marketplace in the sense that the expansions are from third party creators. They are all created by Modartt themselves, one by one over the past 15 years. After all, you can't just sample another instrument, there is a lot more work involved. That might also be the answer why this doesn't yet exists for Organteq. It just takes time. But your reason why you need good selection of expansions might be valuable market insight for Modartt. I know they appreciate feedback, I've talked to them before, so I'd suggest you tell them your concerns.
  - HPsquared 3y ago
    Tuning the model parameters to sound like a sampled piano sounds like an interesting optimization problem.
  - mastazi 3y ago
    > But your reason why you need good selection of expansions might be valuable market insight for Modartt. I know they appreciate feedback, I've talked to them before, so I'd suggest you tell them your concerns. Good point. Disclaimer: I'm just a hobbyist but I know a few professional organists. TL;DR: each organ is unique, pipe organs are not produced in series like pianos. The main reason for people use something like Organteq or Hauptwerk, is usually to practice organ at home. Unlike what happens with other instruments, it is very rare for an average person to own their own pipe organ, so digital reproductions are the way to go for pretty much everyone. But here's the problem: organs are very, very different one another. With piano, you could practice e.g. on a Kawai at home then perform a recital on a Yamaha; the two pianos don't have the same sound and the same action, but they are close enough that you can practice on one instrument then perforom on another. This is not the case with organs: a baroque organ and a romantic organ will be completely different in terms of registrations, pedalboard extension and shape, manuals etc. etc. - not only that but each pipe organ ever built, is a completely custom instrument. For example, all Steinway D-274s ever built, despite some differences due to the year and place of construction, are still the same model (model D-274). But with organs, it's almost never the case that the same organ is built twice. Each single instrument is completely unique, and that's why we identify them by opus number, and we have catalogues of all the organs ever built, like for example this one https://ohta.org.au/organs-of-australia/ https://ohta.org.au/organs-of-australia/ So, the main problem for someone setting up a practice organ is to have access to a digital model that is either that exact organ, or at least a very similar instrument to the one they will use to perform in public. For hobbyists like me who don't plan to perform, there is still a need to at least have a certain type of organ available, because of the great diversity of organs.
skybrian 3y ago
Nice, but someone should do accordion physics.
- weinzierl 3y ago
  Someone did: "Physical-Modelling of Schwyzerörgeli and Accordions" https://www.aramis.admin.ch/Beteiligte/?ProjectID=34490&Sprache=en-US https://www.aramis.admin.ch/Beteiligte/?ProjectID=34490&Spra... There is also a real accordion made by Roland that produces sound electronically. It claims to use physical modeling. https://www.roland.com/uk/products/fr-5b/ https://www.roland.com/uk/products/fr-5b/
  - skybrian 3y ago
    Interesting. I meant publishing how it works, though. There doesn't seem to be any paper associated with that project, that I can see? I suppose I could write to them. The accordionists I know don't think the accordion sound of Roland digital accordions is all that good, though many still use them.
TexanFeller 3y ago
I’m strangely interested in pipe organs, largely because to my ear Toccatta and Fugue in D Minor(BWV 565) is one of the most thrilling pieces of music, like something sent from heaven. It saddens me that people just think of it as a tune to play at Halloween and in vampire movies.
- jacquesm 3y ago
  It's amazing. There are also some piano renderings that are quite impressive but on an organ it really comes into its own. It's also probably the only organ piece that many people know. As for it being sent from heaven: Bach is absolutely un-earthly both in the quality and the quantity of his output. Given the state of the art at the time he gave it such a huge move forward you have to wonder where we'd be today musically if not for him.
  - defrost 3y ago
    And that 1970s prog rock cover: https://www.youtube.com/watch?v=QgbgUrp1a70 https://www.youtube.com/watch?v=QgbgUrp1a70 That said, it shines on a real auditorium sized pipe organ. > you have to wonder where we'd be today musically if not for him. Err, probably using lute music[1] transposed for organ[2] and adapted[3] as film soundtracks[4] I guess. [1] https://www.youtube.com/watch?v=yM6hd8EPFl0 https://www.youtube.com/watch?v=yM6hd8EPFl0 [2] https://www.youtube.com/watch?v=_Nf3eU-Y6Ew https://www.youtube.com/watch?v=_Nf3eU-Y6Ew [3] https://www.youtube.com/watch?v=TQ9_6W6bVoQ https://www.youtube.com/watch?v=TQ9_6W6bVoQ [4] https://www.youtube.com/watch?v=Adv9gYQWqb8 https://www.youtube.com/watch?v=Adv9gYQWqb8
    - jacquesm 3y ago
      Too late at night here to play this on the speakers but I'll certainly get to it tomorrow morning. Thank you!
    - jacquesm 3y ago
      Wow! I never saw this before and I don't know how I missed it. Also, that video is decades ahead of its time.
NoZebra120vClip 3y ago
My Catholic diocese has enjoyed a significant recent tradition of love for sacred music, and to that end, several churches have installed very recent and modern pipe organs as a very permanent and enduring support for congregational worship. Our prior bishop wrote a series of documents on sacred music, and two of the churches which have installed brand-new organs are the Cathedral and the Basilica. I am not sure that Roman Catholics, much less the general public, understand the critical role played by a pipe organ in choral singing and leading the assembly. There is absolutely no comparison: not a percussive piano banging on metal strings, not a plectrum on a lute such as guitar, no synthesizer can come anywhere close. Electronic organs can approximate the sound, but not the feel, grandeur, and mighty power of a full-throated organ. The reason that liturgical Christians have used pipe organs is because of the close approximation of the human voice from the very pipes. A pipe organ works (needless to say) by passing air through columns and making it vibrate at specific frequencies. This is very close to the mechanism used in the human voice. Therefore, it is effortless, even for an inexperienced singer, to summon up a passable tune when led by a competent organist. There are myriad cues which can be employed to wordlessly signal when singing will start and stop, and whether the upcoming strophe is proper to a soloist, the choir, or the whole assembly to come in at once. In my days at a chorister, we did indeed rely on grand piano, acoustic guitars, eletronic 1980s-tech organ, and even drums/bass/violin, so unfortunately I did not enjoy much choral experience next to an authentic pipe organ. But now I worship from the pews with one of the best instruments in hundreds of miles, an experienced dedicated schola, and a skilled professional organist/director. Needless to say, it was a breathtaking and gorgeous Christmas as we added a brass ensemble and sang our hearts out. Pipe organs never fail to disappoint the tech nerd in us. My own cathedral has a special camera which they use every week, during live streams, to display the manual as the organist plays it, and believe me, pipe organs are cutting-edge tech nowadays, using computer monitors, interfaces, MIDI and all the trappings, to produce good old-fashioned sound from real pipes. I feel it is truly a unique traditional instrument that can be the best of both worlds, and indeed our own church affirms its "pride of place" in liturgical worship at all times.
- mrob 3y ago
  I don't think a pipe organ is a particularly close approximation of a human voice, because there's no musically controlled dynamic expression within the note. By this I mean each pipe can only produce the sound of the note turning on, the sound of the note sustaining, and the sound of the note decaying, and these are substantially the same every time. (There are subtle differences, because the air flow depends on the state of other pipes playing at the same time, but this is not something musicians actively control, and is traditionally considered a defect to be minimized in high quality organs). It's possible to modify the sound with a tremulant or a swell box, but these are crude compared to what a skilled singer can do. Compare the expression you can get out of a saxophone by varying embouchure and breathing. A saxophone can produce a range of timbres, and the player can dynamically vary the timbre over time. It's mechanically similar to a reed pipe, but the player has far more control over it. And a flute is similar to a flue pipe, again with the player having more control over the sound. But a real pipe organ has some measurable advantages. First, the great multitude of independent sound sources. A real pipe organ has a spatial quality that's impossible to reproduce with stereo speakers. People say that the building is a part of the pipe organ, and that's IMO justified because all these sound sources interact with it produce an incredibly complex reverberation field. The sound you hear when you move your head sounds "big" in a way that would require a very complex speaker setup to reproduce. (Maybe high-order Ambisonics could do it.) Second, the non-existent distortion. Big pipe organs have pedal sections that produce very deep and loud bass. On a real pipe organ, this is a pure harmonic sound (like all wind instruments, bowed strings, and voice). But deep and loud bass is difficult to reproduce with speakers, so there will be substantial non-linearity. If you're reproducing only a single harmonic note, this will only result in harmonic distortion. Harmonic distortion is no big deal, because it's effectively the same thing as changing the voicing of the pipe. You can filter the recorded/synthesized sound to compensate. But if you're trying to play multiple notes at once with the same speaker, you'll get intermodulation distortion, which adds a "muddy" inharmonic sound you never get from real pipes. The only solution here is adding more speakers, especially for bass notes, but again you're increasing cost and complexity. I don't know how complex a sound system would need to be to reproduce a pipe organ such that a skilled listener couldn't distinguish it in an ABX test from the real thing. It would be very difficult to test, because the two would interact with each other acoustically if they were in the same building, and an ABX test requires rapid switching. But in any case, I think most people simulating pipe organs aren't even trying to pass this theoretical test. All this means there is still a place for traditional pipe organs, and if you've never heard one in person I recommend trying it.
hatsunearu 3y ago
Resonance, oscillation, vibration, etc is such a universal topic in engineering with a delightfully simple core and common mathematical background that anyone that is deeply familiar with it in their field should be able to find the beauty in oscillations in other fields.
- wizardforhire 3y ago
  Spoiler alert: everything is an oscillating field
swayvil 3y ago
Has anybody modeled those singing bowls? That's a serious sine wave. Or I guess you could just generate a sine wave.
mrob 3y ago
If you're interested in this, Colin Pykett has a web site containing many detailed articles about the physics and history of pipe organs: https://www.colinpykett.org.uk/completed_work.htm https://www.colinpykett.org.uk/completed_work.htm
- praash 3y ago
  Wow. This site is stunning in both the variety and the number of articles. Thanks for sharing!
yardshop 3y ago
For anyone interested in another good source of pipe organ music, the public radio show Pipedreams makes their shows available on their website: https://www.pipedreams.org/ https://www.pipedreams.org/ Lots of wonderful music and related stories. Great for testing out PA systems! =)
- tgv 3y ago
  Note that American pipe organs sound rather different from (typical) French, English and the German/Dutch instruments. Usually the acoustic is also drier. If you want to hear bass, you should look for organs with a 32' register. Those pipes are indeed 32 foot tall, and the lowest note is barely audible.
  - jacquesm 3y ago
    In Atlantic City and in Sidney there are organs that have 64' ranks!
justinl33 3y ago
> * Organ pipes are DC/AC converters!* Mind = blown. Somehow this made it click for me how electrical DC/AC converters work.
dhosek 3y ago
It’s not mentioned, but the bourdon pipe (used for the lowest pitch pipes) is a stopped pipe, which means it overblows at the twelfth rather than the octave, which is why you don’t see the second harmonic in the frequency analysis like you do with the two shorter pipes.
Cthulhu_ 3y ago
Organ building is a slowly dying art, with the companies building and maintaining them slowly going out of business. We have loads of churches and church organs in the Netherlands still, so there still is some business, but at the same time a lot of them are being replaced by digital keyboards. I have a cousin who is a professional organ player, he gets to play on the big ones, he's a composer and conductor, he's recorded a few albums and the like. "Small fry" in the bigger music world, but he's one of the people keeping the tradition and craftsmanship alive. I had a look on his website (I don't really keep up with family much), he plays on 150, nearly 200 year old organs sometimes.
- jacquesm 3y ago
  Indeed, and it's a great loss. If there is one thing I respect religion for then it is the music and the centuries long maintenance of some of the greatest (in every sense of the word) musical instruments that humanity has produced. I still have this dream of making a small pipe organ one day.
bobim 3y ago
Is there evidence that the pipe harmonic response can be neglected so the audio signature can be extracted solely from the acoustic cavity modes? I’m tempted to run an harmonic analysis of the fluid-structure system to figure this out…
- jacquesm 3y ago
  If you're prepared to model the church as well (or at least the ranks chamber) then you can probably make that work. The interesting part about a church organ is that the harmonics mix pretty much only in the air, not on a soundboard. that gives some interesting challenges in that you need to know more or less exactly how the pipes themselves are arranged in space and church organ designers used this extensively in placing pipes that sound good harmonically in close proximity.
  - bobim 3y ago
    Meshing the building volume at 20 points per wavelength at 20 kHz is going to require around 10^15 elements. Untractable with today’s hardware… Modelling detailed individual sound sources and mixing their contributions at a particular point in space would be doable though. My point was more oriented toward the effect of the pipe on the sound, e.g. the big square wooden ones probably bring something different than the metallic circular pipes.
onewheeltom 3y ago
There is nothing like being in the space during an organ concert or church service. Shock and awe.
- julian_t 3y ago
  I'd really love to have been in the Albert Hall to hear this: https://www.youtube.com/watch?v=AdyAF9M3XVw https://www.youtube.com/watch?v=AdyAF9M3XVw

145 points by praash 3y ago

Would love to play around with this and hear the differences in sound. Something like what this guy did with the engine simulator https://www.youtube.com/watch?v=RKT-sKtR970 https://www.youtube.com/watch?v=RKT-sKtR970

squarefoot 3y ago
Interesting. I can totally see a similar software used to add combustion engines sounds to electric cars through hidden external speakers, possibly also as a service by manufacturers. edit: it appears to work well on Linux through WINE.
- jacquesm 3y ago
  BMW already does this in their i8. It's complete crap.

mastazi 3y ago

Physical modelling has come a long way since it first appeared. Many of the instruments included in the Arturia V Collection (one of the most common collections of instrument plug ins) are made using physical modelling [1]. Modartt's products (even more so than Arturia) offer amazing control over the physical model, with the ability to configure per-note parameters [2]. Speaking of virtual pipe organs, for Organteq to compete with the market leader, Hauptwerk (which is sample-based) there needs to be a good choice of expansions though. With Hauptwerk, you can download hundreds of different organs from all around the world [3]. Modartt has an expansions marketplace for Pianoteq [4], why is the same thing not available for Organteq? [1] https://www.arturia.com/phi https://www.arturia.com/phi [2] https://www.modartt.com/pianoteq_pro https://www.modartt.com/pianoteq_pro [3] https://www.hauptwerk.com/instruments/ https://www.hauptwerk.com/instruments/ [4] https://www.modartt.com/pianoteq_instruments https://www.modartt.com/pianoteq_instruments

Darthy 3y ago
I don't think [4] is a marketplace in the sense that the expansions are from third party creators. They are all created by Modartt themselves, one by one over the past 15 years. After all, you can't just sample another instrument, there is a lot more work involved. That might also be the answer why this doesn't yet exists for Organteq. It just takes time. But your reason why you need good selection of expansions might be valuable market insight for Modartt. I know they appreciate feedback, I've talked to them before, so I'd suggest you tell them your concerns.
- HPsquared 3y ago
  Tuning the model parameters to sound like a sampled piano sounds like an interesting optimization problem.
- mastazi 3y ago
  > But your reason why you need good selection of expansions might be valuable market insight for Modartt. I know they appreciate feedback, I've talked to them before, so I'd suggest you tell them your concerns. Good point. Disclaimer: I'm just a hobbyist but I know a few professional organists. TL;DR: each organ is unique, pipe organs are not produced in series like pianos. The main reason for people use something like Organteq or Hauptwerk, is usually to practice organ at home. Unlike what happens with other instruments, it is very rare for an average person to own their own pipe organ, so digital reproductions are the way to go for pretty much everyone. But here's the problem: organs are very, very different one another. With piano, you could practice e.g. on a Kawai at home then perform a recital on a Yamaha; the two pianos don't have the same sound and the same action, but they are close enough that you can practice on one instrument then perforom on another. This is not the case with organs: a baroque organ and a romantic organ will be completely different in terms of registrations, pedalboard extension and shape, manuals etc. etc. - not only that but each pipe organ ever built, is a completely custom instrument. For example, all Steinway D-274s ever built, despite some differences due to the year and place of construction, are still the same model (model D-274). But with organs, it's almost never the case that the same organ is built twice. Each single instrument is completely unique, and that's why we identify them by opus number, and we have catalogues of all the organs ever built, like for example this one https://ohta.org.au/organs-of-australia/ https://ohta.org.au/organs-of-australia/ So, the main problem for someone setting up a practice organ is to have access to a digital model that is either that exact organ, or at least a very similar instrument to the one they will use to perform in public. For hobbyists like me who don't plan to perform, there is still a need to at least have a certain type of organ available, because of the great diversity of organs.

skybrian 3y ago

Nice, but someone should do accordion physics.

weinzierl 3y ago
Someone did: "Physical-Modelling of Schwyzerörgeli and Accordions" https://www.aramis.admin.ch/Beteiligte/?ProjectID=34490&Sprache=en-US https://www.aramis.admin.ch/Beteiligte/?ProjectID=34490&Spra... There is also a real accordion made by Roland that produces sound electronically. It claims to use physical modeling. https://www.roland.com/uk/products/fr-5b/ https://www.roland.com/uk/products/fr-5b/
- skybrian 3y ago
  Interesting. I meant publishing how it works, though. There doesn't seem to be any paper associated with that project, that I can see? I suppose I could write to them. The accordionists I know don't think the accordion sound of Roland digital accordions is all that good, though many still use them.

TexanFeller 3y ago

I’m strangely interested in pipe organs, largely because to my ear Toccatta and Fugue in D Minor(BWV 565) is one of the most thrilling pieces of music, like something sent from heaven. It saddens me that people just think of it as a tune to play at Halloween and in vampire movies.

jacquesm 3y ago
It's amazing. There are also some piano renderings that are quite impressive but on an organ it really comes into its own. It's also probably the only organ piece that many people know. As for it being sent from heaven: Bach is absolutely un-earthly both in the quality and the quantity of his output. Given the state of the art at the time he gave it such a huge move forward you have to wonder where we'd be today musically if not for him.
- defrost 3y ago
  And that 1970s prog rock cover: https://www.youtube.com/watch?v=QgbgUrp1a70 https://www.youtube.com/watch?v=QgbgUrp1a70 That said, it shines on a real auditorium sized pipe organ. > you have to wonder where we'd be today musically if not for him. Err, probably using lute music[1] transposed for organ[2] and adapted[3] as film soundtracks[4] I guess. [1] https://www.youtube.com/watch?v=yM6hd8EPFl0 https://www.youtube.com/watch?v=yM6hd8EPFl0 [2] https://www.youtube.com/watch?v=_Nf3eU-Y6Ew https://www.youtube.com/watch?v=_Nf3eU-Y6Ew [3] https://www.youtube.com/watch?v=TQ9_6W6bVoQ https://www.youtube.com/watch?v=TQ9_6W6bVoQ [4] https://www.youtube.com/watch?v=Adv9gYQWqb8 https://www.youtube.com/watch?v=Adv9gYQWqb8
  - jacquesm 3y ago
    Too late at night here to play this on the speakers but I'll certainly get to it tomorrow morning. Thank you!
  - jacquesm 3y ago
    Wow! I never saw this before and I don't know how I missed it. Also, that video is decades ahead of its time.

NoZebra120vClip 3y ago

My Catholic diocese has enjoyed a significant recent tradition of love for sacred music, and to that end, several churches have installed very recent and modern pipe organs as a very permanent and enduring support for congregational worship. Our prior bishop wrote a series of documents on sacred music, and two of the churches which have installed brand-new organs are the Cathedral and the Basilica. I am not sure that Roman Catholics, much less the general public, understand the critical role played by a pipe organ in choral singing and leading the assembly. There is absolutely no comparison: not a percussive piano banging on metal strings, not a plectrum on a lute such as guitar, no synthesizer can come anywhere close. Electronic organs can approximate the sound, but not the feel, grandeur, and mighty power of a full-throated organ. The reason that liturgical Christians have used pipe organs is because of the close approximation of the human voice from the very pipes. A pipe organ works (needless to say) by passing air through columns and making it vibrate at specific frequencies. This is very close to the mechanism used in the human voice. Therefore, it is effortless, even for an inexperienced singer, to summon up a passable tune when led by a competent organist. There are myriad cues which can be employed to wordlessly signal when singing will start and stop, and whether the upcoming strophe is proper to a soloist, the choir, or the whole assembly to come in at once. In my days at a chorister, we did indeed rely on grand piano, acoustic guitars, eletronic 1980s-tech organ, and even drums/bass/violin, so unfortunately I did not enjoy much choral experience next to an authentic pipe organ. But now I worship from the pews with one of the best instruments in hundreds of miles, an experienced dedicated schola, and a skilled professional organist/director. Needless to say, it was a breathtaking and gorgeous Christmas as we added a brass ensemble and sang our hearts out. Pipe organs never fail to disappoint the tech nerd in us. My own cathedral has a special camera which they use every week, during live streams, to display the manual as the organist plays it, and believe me, pipe organs are cutting-edge tech nowadays, using computer monitors, interfaces, MIDI and all the trappings, to produce good old-fashioned sound from real pipes. I feel it is truly a unique traditional instrument that can be the best of both worlds, and indeed our own church affirms its "pride of place" in liturgical worship at all times.

mrob 3y ago
I don't think a pipe organ is a particularly close approximation of a human voice, because there's no musically controlled dynamic expression within the note. By this I mean each pipe can only produce the sound of the note turning on, the sound of the note sustaining, and the sound of the note decaying, and these are substantially the same every time. (There are subtle differences, because the air flow depends on the state of other pipes playing at the same time, but this is not something musicians actively control, and is traditionally considered a defect to be minimized in high quality organs). It's possible to modify the sound with a tremulant or a swell box, but these are crude compared to what a skilled singer can do. Compare the expression you can get out of a saxophone by varying embouchure and breathing. A saxophone can produce a range of timbres, and the player can dynamically vary the timbre over time. It's mechanically similar to a reed pipe, but the player has far more control over it. And a flute is similar to a flue pipe, again with the player having more control over the sound. But a real pipe organ has some measurable advantages. First, the great multitude of independent sound sources. A real pipe organ has a spatial quality that's impossible to reproduce with stereo speakers. People say that the building is a part of the pipe organ, and that's IMO justified because all these sound sources interact with it produce an incredibly complex reverberation field. The sound you hear when you move your head sounds "big" in a way that would require a very complex speaker setup to reproduce. (Maybe high-order Ambisonics could do it.) Second, the non-existent distortion. Big pipe organs have pedal sections that produce very deep and loud bass. On a real pipe organ, this is a pure harmonic sound (like all wind instruments, bowed strings, and voice). But deep and loud bass is difficult to reproduce with speakers, so there will be substantial non-linearity. If you're reproducing only a single harmonic note, this will only result in harmonic distortion. Harmonic distortion is no big deal, because it's effectively the same thing as changing the voicing of the pipe. You can filter the recorded/synthesized sound to compensate. But if you're trying to play multiple notes at once with the same speaker, you'll get intermodulation distortion, which adds a "muddy" inharmonic sound you never get from real pipes. The only solution here is adding more speakers, especially for bass notes, but again you're increasing cost and complexity. I don't know how complex a sound system would need to be to reproduce a pipe organ such that a skilled listener couldn't distinguish it in an ABX test from the real thing. It would be very difficult to test, because the two would interact with each other acoustically if they were in the same building, and an ABX test requires rapid switching. But in any case, I think most people simulating pipe organs aren't even trying to pass this theoretical test. All this means there is still a place for traditional pipe organs, and if you've never heard one in person I recommend trying it.

hatsunearu 3y ago

Resonance, oscillation, vibration, etc is such a universal topic in engineering with a delightfully simple core and common mathematical background that anyone that is deeply familiar with it in their field should be able to find the beauty in oscillations in other fields.

wizardforhire 3y ago
Spoiler alert: everything is an oscillating field

swayvil 3y ago

Has anybody modeled those singing bowls? That's a serious sine wave. Or I guess you could just generate a sine wave.

mrob 3y ago

If you're interested in this, Colin Pykett has a web site containing many detailed articles about the physics and history of pipe organs: https://www.colinpykett.org.uk/completed_work.htm https://www.colinpykett.org.uk/completed_work.htm

praash 3y ago
Wow. This site is stunning in both the variety and the number of articles. Thanks for sharing!

yardshop 3y ago

For anyone interested in another good source of pipe organ music, the public radio show Pipedreams makes their shows available on their website: https://www.pipedreams.org/ https://www.pipedreams.org/ Lots of wonderful music and related stories. Great for testing out PA systems! =)

tgv 3y ago
Note that American pipe organs sound rather different from (typical) French, English and the German/Dutch instruments. Usually the acoustic is also drier. If you want to hear bass, you should look for organs with a 32' register. Those pipes are indeed 32 foot tall, and the lowest note is barely audible.
- jacquesm 3y ago
  In Atlantic City and in Sidney there are organs that have 64' ranks!

justinl33 3y ago

> * Organ pipes are DC/AC converters!* Mind = blown. Somehow this made it click for me how electrical DC/AC converters work.

dhosek 3y ago

It’s not mentioned, but the bourdon pipe (used for the lowest pitch pipes) is a stopped pipe, which means it overblows at the twelfth rather than the octave, which is why you don’t see the second harmonic in the frequency analysis like you do with the two shorter pipes.

Cthulhu_ 3y ago

Organ building is a slowly dying art, with the companies building and maintaining them slowly going out of business. We have loads of churches and church organs in the Netherlands still, so there still is some business, but at the same time a lot of them are being replaced by digital keyboards. I have a cousin who is a professional organ player, he gets to play on the big ones, he's a composer and conductor, he's recorded a few albums and the like. "Small fry" in the bigger music world, but he's one of the people keeping the tradition and craftsmanship alive. I had a look on his website (I don't really keep up with family much), he plays on 150, nearly 200 year old organs sometimes.

jacquesm 3y ago
Indeed, and it's a great loss. If there is one thing I respect religion for then it is the music and the centuries long maintenance of some of the greatest (in every sense of the word) musical instruments that humanity has produced. I still have this dream of making a small pipe organ one day.

bobim 3y ago

Is there evidence that the pipe harmonic response can be neglected so the audio signature can be extracted solely from the acoustic cavity modes? I’m tempted to run an harmonic analysis of the fluid-structure system to figure this out…

jacquesm 3y ago
If you're prepared to model the church as well (or at least the ranks chamber) then you can probably make that work. The interesting part about a church organ is that the harmonics mix pretty much only in the air, not on a soundboard. that gives some interesting challenges in that you need to know more or less exactly how the pipes themselves are arranged in space and church organ designers used this extensively in placing pipes that sound good harmonically in close proximity.
- bobim 3y ago
  Meshing the building volume at 20 points per wavelength at 20 kHz is going to require around 10^15 elements. Untractable with today’s hardware… Modelling detailed individual sound sources and mixing their contributions at a particular point in space would be doable though. My point was more oriented toward the effect of the pipe on the sound, e.g. the big square wooden ones probably bring something different than the metallic circular pipes.

onewheeltom 3y ago

There is nothing like being in the space during an organ concert or church service. Shock and awe.

julian_t 3y ago
I'd really love to have been in the Albert Hall to hear this: https://www.youtube.com/watch?v=AdyAF9M3XVw https://www.youtube.com/watch?v=AdyAF9M3XVw