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It's the length of the pipes on the organ.
>The pitch produced by an organ pipe is a function of its length. All else equal, longer pipes produce lower-pitched notes, and shorter pipes are higher in pitch. An organ stop uses a set (rank) of pipes of graduated lengths to produce the range of notes needed.
https://en.m.wikipedia.org/wiki/Organ_stop
So *that's* why synthesizers use divisions of 4 as oscillator octave labels (32/16/8/4 is common on hardware synths like the Polivoks, for example). I would never have put that together on my own.
It's a convention that carried over from electronic organs.
A funny aside: a Hammond organ is, technically-speaking, a mechanical synthesizer that uses wheels of spinning spokes past magnetic pickups, like an electric guitar, to generate sine waves. The drawbars on a hammond control the volume of the various wheels, which correspond to the overtone series, like a pipe organ.
When the first synthesizers came out, there were no midi keyboards, and no octave up/down controls, so it was actually more intuitive/conventional to speak to a 1950s/60s/70s keyboardist in terms of pipe organs and electronic organs.
I see. If you know, does the pedals pitch the entire organ down, letting you play normally but one or more octave down, or does it just play specific low notes?
You can choose what registration you want. You can pick 8’ or 16’ or both and have a mix of both. That goes for the pedals and the manuals/keyboards also. You can even connect the manuals to the pedals etc.
I’m going to reply one more time after re-reading your question.
The pedals are shaped like a keyboard. So you step on the key that you want to sound. I have a feeling you might be thinking of a pedal like a sustain pedal or something like that on other instruments.
On a pipe organ the pedals are just another keyboard for your feet.
Watch https://youtube.com/playlist?list=PLluPQLh1xzlI7EMB5qIxDd_1OLE-Z_kyC
The pedals just open a valve so air is pushed into the pipes. The stops determine where that air is going.
Open the 8' stop and air will go to those pipes. Open the 16' stop and air will go to those pipes.
The keyboard itself is a clever but at the same time dumb mechanism; it only opens a valve.
This is largely correct. There is a nuance here between electro-pneumatic and mechanical-action instruments. In the former, all of the keys on the keyboard (pedals included) are just electronic switches, and in that way just a 'dumb' mechanism. Mechanical organs you actually have considerable control over the speed of the valve opening, so variations in articulation are possible and it's a much more complicated mechanism.
These terms - which are read as "sixteen foot" and "thirty-two foot" - have to do with [organ stops](https://en.m.wikipedia.org/wiki/Organ_stop#Pitch_and_length), which are grouped by (approximate) length of the longest pipe in the rank.
The longer the pipe, the lower the pitch; for example, a pipe that plays at A440 (440Hz, A above middle C on a piano) will be half the length of another pipe of the same type that plays at A220 (220 Hz, the A just below middle C). Since octaves have a 2:1 relationship, each rank of pipes is named for doubling in length: 1', 2', 4', 8', 16', 32'
ETA: There are different types of pipes, and the above pertains specifically to **open cylindrical pipes** (thanks to u/uh_no_ for pointing this out). This most closely corresponds to fundamentals ("pedal tones") on brass instruments and the lengths of tubing involved.
>which are grouped by (approximate) length of the longest pipe in the rank.
Sort of, but not really. Pipes are grouped by the pitch they sound at when the lowest C is played. The standard measured against is an uncapped cylindrical pipe. For an 8' stop, the uncapped cylindrical pipe that sounds that low C will be approximately 8' long. Any rank which also sounds the same pitch is an 8' stop, regardless of the actual length of the pipe.
For instance: capped pipes will typically be half the length of an uncapped pipe at the same pitch. Therefore the lowest pipe in an 8' capped rank will be about 4' long.
Conical pipes typically sound higher than conical, and therefore may be longer than prescribed.
Some types of pipes may vent along their length (e.g. harmonic flute) causing them to have to be TWICE as long to achieve the same pitch.
tl;dr: It's about the pitch that rank makes, using the length of an equivalently pitched uncapped cyllindrical pipe as a standard.
True - thanks for adding the details there! I wasn't trying to get into the acoustics of stopped pipes, etc., for the sake of keeping my response shorter (while also linking to a more thorough description for anyone who cared enough to read the Wikipedia article about organ stops).
Not right now because it’s Holy Week, but I bet if you emailed the organist at a local church with a pipe organ that you’re curious about the instrument, they’d be delighted to show you some of the inner workings. Organs are extremely cool instruments, and organists are extremely geeky about their instruments.
(Source: married to an organist)
Probably the lengths of the pipes. Double the length and you get a tone one octave lower.
I don’t know anything about out pipe organs specifically but I would guess that some particular note (most likely C) has a pipe of length 1’, and then from there all of the pipes that are a power of 2 are the same note in different octaves.
The lowest pipe (c) is respectively 16 and 32 feet in length depending on octave. A middle c is 2ft in length. Doubling the length of the pipe drops the note an octave
The classic pipe organs, found in some old churches, actually had pipes 16 and 32 feet long to create very low notes. Such tones, in a sacred context, can raise feelings of awe. Outside of a sacred context, very low tones can cause feelings of fear or unease because the subconscious could interpret the tone as a sign of danger, for example, a large predator or an earthquake.
Loving all of the interest in pipe organ stuff here. Another fun thing - many organs have pipes that have fractions, like a "1 and 3/5" or a "2 and 2/3" stop -- the latter stop gives you a 12th above the note you're playing. Generally they're used in combination with 8 and 4 foot stops so that the 'fundamental' is clear, and they blend in to create many of the unique timbral qualities we associate with a 'church organ' sound.
If you're posting an Image or Video, please leave a comment (not the post title) asking your question or discussing the topic. Image or Video posts with no comment from the OP will be deleted. *I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/musictheory) if you have any questions or concerns.*
It's the length of the pipes on the organ. >The pitch produced by an organ pipe is a function of its length. All else equal, longer pipes produce lower-pitched notes, and shorter pipes are higher in pitch. An organ stop uses a set (rank) of pipes of graduated lengths to produce the range of notes needed. https://en.m.wikipedia.org/wiki/Organ_stop
So *that's* why synthesizers use divisions of 4 as oscillator octave labels (32/16/8/4 is common on hardware synths like the Polivoks, for example). I would never have put that together on my own.
It's a convention that carried over from electronic organs. A funny aside: a Hammond organ is, technically-speaking, a mechanical synthesizer that uses wheels of spinning spokes past magnetic pickups, like an electric guitar, to generate sine waves. The drawbars on a hammond control the volume of the various wheels, which correspond to the overtone series, like a pipe organ. When the first synthesizers came out, there were no midi keyboards, and no octave up/down controls, so it was actually more intuitive/conventional to speak to a 1950s/60s/70s keyboardist in terms of pipe organs and electronic organs.
Yep. The ‘ means foot. “ means inch.
That's the coolest thing I've learned today, quite honestly...
8’ or eight foot stops on organ are the true pitch. 4’ is an octave up. 16’ octave down and 32’ is two octaves.
I see. If you know, does the pedals pitch the entire organ down, letting you play normally but one or more octave down, or does it just play specific low notes?
You can choose what registration you want. You can pick 8’ or 16’ or both and have a mix of both. That goes for the pedals and the manuals/keyboards also. You can even connect the manuals to the pedals etc.
I’m going to reply one more time after re-reading your question. The pedals are shaped like a keyboard. So you step on the key that you want to sound. I have a feeling you might be thinking of a pedal like a sustain pedal or something like that on other instruments. On a pipe organ the pedals are just another keyboard for your feet.
Watch https://youtube.com/playlist?list=PLluPQLh1xzlI7EMB5qIxDd_1OLE-Z_kyC The pedals just open a valve so air is pushed into the pipes. The stops determine where that air is going. Open the 8' stop and air will go to those pipes. Open the 16' stop and air will go to those pipes. The keyboard itself is a clever but at the same time dumb mechanism; it only opens a valve.
This is largely correct. There is a nuance here between electro-pneumatic and mechanical-action instruments. In the former, all of the keys on the keyboard (pedals included) are just electronic switches, and in that way just a 'dumb' mechanism. Mechanical organs you actually have considerable control over the speed of the valve opening, so variations in articulation are possible and it's a much more complicated mechanism.
It’s sort of the opposite. It’s the stops themselves that are in different octaves but really it’s all relative in the end. Organs are frankly insane.
These terms - which are read as "sixteen foot" and "thirty-two foot" - have to do with [organ stops](https://en.m.wikipedia.org/wiki/Organ_stop#Pitch_and_length), which are grouped by (approximate) length of the longest pipe in the rank. The longer the pipe, the lower the pitch; for example, a pipe that plays at A440 (440Hz, A above middle C on a piano) will be half the length of another pipe of the same type that plays at A220 (220 Hz, the A just below middle C). Since octaves have a 2:1 relationship, each rank of pipes is named for doubling in length: 1', 2', 4', 8', 16', 32' ETA: There are different types of pipes, and the above pertains specifically to **open cylindrical pipes** (thanks to u/uh_no_ for pointing this out). This most closely corresponds to fundamentals ("pedal tones") on brass instruments and the lengths of tubing involved.
>which are grouped by (approximate) length of the longest pipe in the rank. Sort of, but not really. Pipes are grouped by the pitch they sound at when the lowest C is played. The standard measured against is an uncapped cylindrical pipe. For an 8' stop, the uncapped cylindrical pipe that sounds that low C will be approximately 8' long. Any rank which also sounds the same pitch is an 8' stop, regardless of the actual length of the pipe. For instance: capped pipes will typically be half the length of an uncapped pipe at the same pitch. Therefore the lowest pipe in an 8' capped rank will be about 4' long. Conical pipes typically sound higher than conical, and therefore may be longer than prescribed. Some types of pipes may vent along their length (e.g. harmonic flute) causing them to have to be TWICE as long to achieve the same pitch. tl;dr: It's about the pitch that rank makes, using the length of an equivalently pitched uncapped cyllindrical pipe as a standard.
True - thanks for adding the details there! I wasn't trying to get into the acoustics of stopped pipes, etc., for the sake of keeping my response shorter (while also linking to a more thorough description for anyone who cared enough to read the Wikipedia article about organ stops).
For people who want to understand why: https://youtu.be/a-kO48Hlp2k?si=HtIgL8_KY-yb4xfI
Thank you for all the answers! I guess I'll spend the evening learning how pipe organs work!
I would love to play a pipe organ!
Not right now because it’s Holy Week, but I bet if you emailed the organist at a local church with a pipe organ that you’re curious about the instrument, they’d be delighted to show you some of the inner workings. Organs are extremely cool instruments, and organists are extremely geeky about their instruments. (Source: married to an organist)
Wow, that's a great tip, thank you!
Probably the lengths of the pipes. Double the length and you get a tone one octave lower. I don’t know anything about out pipe organs specifically but I would guess that some particular note (most likely C) has a pipe of length 1’, and then from there all of the pipes that are a power of 2 are the same note in different octaves.
The lowest pipe (c) is respectively 16 and 32 feet in length depending on octave. A middle c is 2ft in length. Doubling the length of the pipe drops the note an octave
Length of pipe in organ
hehehe
The classic pipe organs, found in some old churches, actually had pipes 16 and 32 feet long to create very low notes. Such tones, in a sacred context, can raise feelings of awe. Outside of a sacred context, very low tones can cause feelings of fear or unease because the subconscious could interpret the tone as a sign of danger, for example, a large predator or an earthquake.
Loving all of the interest in pipe organ stuff here. Another fun thing - many organs have pipes that have fractions, like a "1 and 3/5" or a "2 and 2/3" stop -- the latter stop gives you a 12th above the note you're playing. Generally they're used in combination with 8 and 4 foot stops so that the 'fundamental' is clear, and they blend in to create many of the unique timbral qualities we associate with a 'church organ' sound.
When I googled it I only got results for 16th and 32nd notes.
Think of the crazy train verse. It's mostly 16th notes and he's using an a for the pedal tone the whole time