4 ms·

> If so, how come a church organ doesn't sound like a chip tune, which is also built up from simple waveforms? Well, actually it will, if you remove the church.

> If so, how come a church organ doesn't sound like a chip tune, which is also built up from simple waveforms? Well, actually it will, if you remove the church. That's not true. In the real world an acoustic device will never generate a pure sound. An organ pipe will generate all sorts of artifact noises and its overall sonic behaviour will be affected by temperature, humidity, barometric pressure, and its physical promixity to other pipes (interference is a common problem in mixtures). It is important to note that organ builders will graduate the different pipe dimensions within a single register in order to achieve a homogeneous sound from low to high notes, but that graduation does not necessarily follow physical laws but rather an approximation. Sometimes the graduation will involve jumps or repetition in order to create a register with a mixed character. Finally, the voicing of individual pipes, done by hand, will (when done by a master voicer) balance character and homogeneity. Each register will have its own personality, but each note will sound slightly different. > You have to add movement, energy, and emphasis (which, on an organ, has to be implemented by varying the duration of the notes, and the pauses between them, because there's no dynamic response). On mechanical organs, a good player will also be able to adjust the opening and closing of individual pallets (valves) using their fingers, in order to control the attack and decay of individual notes.

Gibbon1 7y ago
I remember an accountant for a company that built and tuned organs talking about their search for field service guy. He said it's a difficult position to fill. A candidate needs perfect pitch. Familiarity with religious sects and church music because the organ needs tuning according to the music played and cultural expectations of the parish[1]. They need to be able to navigate church politics. And be willing to travel to the middle of nowhere on a regular basis. And mechanically adept. [1] He said some music is designed to be played on a rich earthy sounding organ and others on one that more pure and ethereal. Tune the organ the wrong way and they'll horrified what you did.
- mrob 7y ago
  >A candidate needs perfect pitch. Why? Traditionally, organs are tuned by listening to the beats[0] between pairs of notes. If you want to tune to specific frequency (such as the modern A=440Hz standard) you only need a single frequency reference, such as a tuning fork. But historically there have been an enormous variety of tunings used in pipe organs, many of which were built before A=440Hz became standard, and in any case, the tuning is affected by temperature, so it will drift as the seasons change. I think that company is needlessly limiting their options by requiring perfect pitch. Good relative pitch perception is sufficient. [0] https://en.wikipedia.org/wiki/Beat_(acoustics) https://en.wikipedia.org/wiki/Beat_(acoustics)
  - mrob 7y ago
    Too late to edit my post, I thought of a reason. I expect most pipes in old organs are unlabeled. Somebody with perfect pitch can identify them quickly and without needing any electronic device, leaving their hands free for other tasks.
mrob 7y ago
An organ pipe, when played on low to moderate pressure and allowed to reach a steady state, generates a pure harmonic tone. There is only a single audible oscillator (either the column of air in the flue pipe, or the acoustically coupled system of the beating reed and the column of air in a reed pipe), and this oscillator is periodic, so all partials are exact integer multiple of the fundamental. This is not true of all instruments. A string oscillates both by tension along the string and by bending across the string. The bending component becomes especially important with thick strings, so a bass guitar produces noticeably inharmonic sounds. This can make the sound more complex and interesting, but it can also result in "muddy" sounding chords. A hammered string, such as used in a piano, works the same way. Pianos traditionally compensate for this by using "stretched" tuning, i.e. going up an octave is slightly more than a doubling of a frequency. This helps the harmonics of the chords line up with the slightly sharp partials of the inharmonic tone. Another way to avoid the inharmonicity is with bowed strings. Here the slip-stick motion of the bow resets the motion of the string every cycle, like hard sync in a chiptune. The bowed string in steady state is purely harmonic. Tuned percussion instruments have even more oscillators interacting. A marimba bar twists and stretches along many different axis, resulting in a complex inharmonic tone. A skilled tuner can adjust the shape of the bar to bring many of the partials close to integer ratios. The same is true of bells. See https://en.wikipedia.org/wiki/Inharmonicity https://en.wikipedia.org/wiki/Inharmonicity A pipe organ can have a noisy "chiff" at the start of the note, but whether or not this is audible depends on how the pipes are voiced. It has been considered desirable or an unacceptable fault according to the fashions of the time, so there is nothing wrong with omitting it. It is not practical to control how far the pallets are opened by partially depressing the keys. In a mechanical action organ it takes significant force to overcome the initial air pressure, which generally makes the pallet spring all the way open. Pneumatic and electric actions don't even theoretically allow partial opening. I am not aware of any organ composition which calls for partial opening. IMO a filtered chiptune wave, with good quality reverb, makes a excellent organ-like tone.
- TheOtherHobbes 7y ago
  Organ partials aren't perfectly periodic. There's some chaotic pressure variation around the lip, and the pipe also distorts mechanically with pressure variations along the various possible modes - much more than a stiffer instrument played with lower pressure, like a flute. So not only are the partials subtly inharmonic in various ways, they also have different attack envelopes at the start of a note, and the air pressure from the bellows/pump may also vary over time as notes/ranks are played. This is one of those common situations in music where a trivial model is too superficial to capture the defining subtleties of a system. The richness of a full pipe organ is a combination of subtle effects within each pipe, combined with subtle variations within each rank, combined with the not-so-subtle effect of combining multiple ranks, combined with the acoustic environment of the hall, which doesn't just add a generic stereo reverb, but also supports standing waves at some of the lower bass notes. A filtered chiptune wave really isn't a very good approximation.
yomly 7y ago
This is exquisitely interesting level of detail. I've always thought that there was more to the organ I hear than the conceptual mental model of a binary "on/off" smooth tone generated by the organ - thanks for articulating some of the nuances that go organ playing. That said, I can't help but feel you're missing the point of the article though... There's the old quote: "All models are wrong, some are useful" Of the traditional musical instruments we have, I think 8 bit waveforms probably lend themselves well to the organ (more so than other instruments: strings have decay and vibrato, even other keyboard instruments have decay and tonal qualities). Additionally, contrapuntal baroque music probably worked quite well for the constrained environment the hardware provided by way of number of voices and length of music...
gmueckl 7y ago
The most artificial sounding sections in this synth music are those were chords and harmonies are just too perfect and blend together too much. This is caused mainly by two things: perfect tuning and perfect oscillator stability. If one were to mess with both (slight random base offset for each note, even slighter phase drift per note) one would probably get rid of that and generate a more impure, "warmer" sound. The convolution reverb works wonders on the synth output, though.

Gibbon1 7y ago

I remember an accountant for a company that built and tuned organs talking about their search for field service guy. He said it's a difficult position to fill. A candidate needs perfect pitch. Familiarity with religious sects and church music because the organ needs tuning according to the music played and cultural expectations of the parish[1]. They need to be able to navigate church politics. And be willing to travel to the middle of nowhere on a regular basis. And mechanically adept. [1] He said some music is designed to be played on a rich earthy sounding organ and others on one that more pure and ethereal. Tune the organ the wrong way and they'll horrified what you did.

mrob 7y ago
>A candidate needs perfect pitch. Why? Traditionally, organs are tuned by listening to the beats[0] between pairs of notes. If you want to tune to specific frequency (such as the modern A=440Hz standard) you only need a single frequency reference, such as a tuning fork. But historically there have been an enormous variety of tunings used in pipe organs, many of which were built before A=440Hz became standard, and in any case, the tuning is affected by temperature, so it will drift as the seasons change. I think that company is needlessly limiting their options by requiring perfect pitch. Good relative pitch perception is sufficient. [0] https://en.wikipedia.org/wiki/Beat_(acoustics) https://en.wikipedia.org/wiki/Beat_(acoustics)
- mrob 7y ago
  Too late to edit my post, I thought of a reason. I expect most pipes in old organs are unlabeled. Somebody with perfect pitch can identify them quickly and without needing any electronic device, leaving their hands free for other tasks.

mrob 7y ago

An organ pipe, when played on low to moderate pressure and allowed to reach a steady state, generates a pure harmonic tone. There is only a single audible oscillator (either the column of air in the flue pipe, or the acoustically coupled system of the beating reed and the column of air in a reed pipe), and this oscillator is periodic, so all partials are exact integer multiple of the fundamental. This is not true of all instruments. A string oscillates both by tension along the string and by bending across the string. The bending component becomes especially important with thick strings, so a bass guitar produces noticeably inharmonic sounds. This can make the sound more complex and interesting, but it can also result in "muddy" sounding chords. A hammered string, such as used in a piano, works the same way. Pianos traditionally compensate for this by using "stretched" tuning, i.e. going up an octave is slightly more than a doubling of a frequency. This helps the harmonics of the chords line up with the slightly sharp partials of the inharmonic tone. Another way to avoid the inharmonicity is with bowed strings. Here the slip-stick motion of the bow resets the motion of the string every cycle, like hard sync in a chiptune. The bowed string in steady state is purely harmonic. Tuned percussion instruments have even more oscillators interacting. A marimba bar twists and stretches along many different axis, resulting in a complex inharmonic tone. A skilled tuner can adjust the shape of the bar to bring many of the partials close to integer ratios. The same is true of bells. See https://en.wikipedia.org/wiki/Inharmonicity https://en.wikipedia.org/wiki/Inharmonicity A pipe organ can have a noisy "chiff" at the start of the note, but whether or not this is audible depends on how the pipes are voiced. It has been considered desirable or an unacceptable fault according to the fashions of the time, so there is nothing wrong with omitting it. It is not practical to control how far the pallets are opened by partially depressing the keys. In a mechanical action organ it takes significant force to overcome the initial air pressure, which generally makes the pallet spring all the way open. Pneumatic and electric actions don't even theoretically allow partial opening. I am not aware of any organ composition which calls for partial opening. IMO a filtered chiptune wave, with good quality reverb, makes a excellent organ-like tone.

TheOtherHobbes 7y ago
Organ partials aren't perfectly periodic. There's some chaotic pressure variation around the lip, and the pipe also distorts mechanically with pressure variations along the various possible modes - much more than a stiffer instrument played with lower pressure, like a flute. So not only are the partials subtly inharmonic in various ways, they also have different attack envelopes at the start of a note, and the air pressure from the bellows/pump may also vary over time as notes/ranks are played. This is one of those common situations in music where a trivial model is too superficial to capture the defining subtleties of a system. The richness of a full pipe organ is a combination of subtle effects within each pipe, combined with subtle variations within each rank, combined with the not-so-subtle effect of combining multiple ranks, combined with the acoustic environment of the hall, which doesn't just add a generic stereo reverb, but also supports standing waves at some of the lower bass notes. A filtered chiptune wave really isn't a very good approximation.

yomly 7y ago

This is exquisitely interesting level of detail. I've always thought that there was more to the organ I hear than the conceptual mental model of a binary "on/off" smooth tone generated by the organ - thanks for articulating some of the nuances that go organ playing. That said, I can't help but feel you're missing the point of the article though... There's the old quote: "All models are wrong, some are useful" Of the traditional musical instruments we have, I think 8 bit waveforms probably lend themselves well to the organ (more so than other instruments: strings have decay and vibrato, even other keyboard instruments have decay and tonal qualities). Additionally, contrapuntal baroque music probably worked quite well for the constrained environment the hardware provided by way of number of voices and length of music...

gmueckl 7y ago

The most artificial sounding sections in this synth music are those were chords and harmonies are just too perfect and blend together too much. This is caused mainly by two things: perfect tuning and perfect oscillator stability. If one were to mess with both (slight random base offset for each note, even slighter phase drift per note) one would probably get rid of that and generate a more impure, "warmer" sound. The convolution reverb works wonders on the synth output, though.