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stopped & half-stopped pipes

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  • stopped & half-stopped pipes

    I'm not building, maintaining or playing an organ, just trying to understand a term.
    In reading about stopped and half-stopped pipes, I *think* that stopped pipes have, essentially, a metal top, while half-stopped pipes have a tube through that stopper or a conical top that constricts the airflow. Is that correct?
    I also got the impression that the main use of half-stopped pipes is to imitate a flute. Is that accurate?


  • #2

    Welcome to the Forum! I hope you continue to participate here for a time to come.

    You pretty much have the gist of how the stopped pipes work. That said, however, there is much more detail that goes into the sound. First of all, the stoppers are not always metal covers. An example would be the 16' Bourdon or 16' Lieblich Gedeckt in the Pedal often has wooden stoppers that go inside the pipe and are held there by friction ( The "chimney" you see is actually the handle used to adjust the stopper. Needless to say, they are totally stopped pipes. Stopping a pipe has the effect of making the pipe speak an octave lower than if it were open.

    A half-stopped pipe may be a chimney of a certain height (, the chiminey can be inverted inside the pipe, or sometimes it can be a piece of metal anchored on one side of a wooden pipe and bent across the top. The chimney needs to be of a certain length & diameter, and it is there to reinforce a particular partial/harmonic of the overtone series that makes up the note and tone quality.

    It could be said that some stops could be considered half-stopped, like the Gemshorn ( Personally, I don't consider it a stopped pipe because of its inverted conical construction, but depending on how it is constructed, it could be described as half-stopped. I know of at least one source that has.

    What I've given is the bare basics, but hopefully some of our pipe organ builders will weigh in on your thread. You've asked an excellent question! Glad to have you as part of the Forum!

    Way too many organs to list, but I do have 5 Allens:
    • MOS-2 Model 505-B / ADC-4300-DK / ADC-5400 / ADC-6000 (Symphony) / ADC-8000DKC
    • Lowrey Heritage (DSO-1)
    • 11 Pump Organs, 1 Pipe Organ & 7 Pianos


    • #3
      Michael's explanation and link to the website is very helpful, especially with being able to hear the different types.

      I'll add a book learnin' summary, as I was just yesterday reading in Harold Gleason's Method of Organ Playing (6E) in the section "Qualities of Tone Color". In subsection "Flute Tone" he notes the following types: Stopped Flutes, Half-stopped Flutes, Open Flutes, and Harmonic Flutes.

      For the stopped ones (Gedackt, Pommer, Bourdon, Nason Flute, Stopped Diapason, Subbass), they have odd-number partials (2 2/3', 1 3/5') along with a strong fundamental pitch.

      The half-stopped ones (Rohrfloet, Chimney Flute, Koppelflote) have a cylindrical tube in the stopper or a cone-shaped extension on the pipe, and they reinforce the fifth (1 3/5') and sixth (1 1/3') partials.

      The Quintadena family of flutes develop the third partial (2 2/3') [an octave and a fifth above] the fundamental pitch. That is one of easiest to remember as "Quint" is five or fifth--the other emphasized partials rarely get embedded in the flute name.

      If you're sign-upped with the Internet Archive (free), you are likely to find the full text about "Qualities of Tone Color" starting on page 3 of the earlier edition:

      Of course, my above are generalizations and any specific flute stop you hear may vary dramatically from both the description and the audio examples at Why? Because organ builders can be amazingly creative and won't be dictated to by anyone or anything; )

      PS When thinking about organ sound, I should always think "Colin Pykett": his website is awesome for pipe and electronic organ sound information from a professional acoustics viewpoint. An article on the tonal structure of flutes is typical and appropriate to this topic:


      • #4
        Thank you, gentlemen both!

        I apologize, too. I now realize that I should have said in my first message that I'm inquiring because of a limerick, and therefore don't need a whole lot of detail. I hang out at a website with the peculiar and quixotic aim of defining every word in English in a limerick. Every submission goes through a workshop, and I'm one of the people workshopping a verse on "half-stopped." The author described it as being partly covered with leather, which didn't seem right from what I was able to find.

        We're tackling this alphabetically and are somewhere around halfway to O, which is why our musical instruments: keyboard browser topic finds far more accordion verses than ones about organs.

        Do I have this right?

        While the top of a stopped pipe is plugged or covered to drop the note it would otherwise play by an octave, a half-stopped pipe is either topped with a chimney or (if wooden) party covered in metal to imitate the sound of a flute. There are other techniques for making an organ pipe sound flutelike, and organ builders often see this as an opportunity for their own variations on a theme.


        • myorgan
          myorgan commented
          Editing a comment
          It appears to be correct. Just be aware not all half-stopped pipes have a partially covered leather lip. The link to your website did not come up, so I couldn't check the work you've completed already.

          Welcome to the Forum!


        • Michael Shirk
          Michael Shirk commented
          Editing a comment
          The stopper of a wooden stopped pipe is covered with leather on the bottom and sides to make it sit tightly. This is the case even if it's "half-stopped" - that is, if the handle is pierced to make a chimney. So that could be what was meant. This shows a diagram of a wooden stopped pipe with the leather (although you can't see if the handle is pierced.)

      • #5
        A certain young organbuilder from Erenscrute
        Eyed a half finished rank of Hohl flute
        He took a fancy to C4 but got trapped in the shute
        Now poor C4 cannot toot


        • #6
          Thanks, Michael and Michael Shirk!
          And thanks for the grin, Leisesturm. :D Is C4 the biggest pipe?

          Michael -- Something else I'd forgotten is that OEDILF's server is, apparently, so old that it can't meet current https standards, so a lot of browser software runs away from it shrieking in horror. However, we don't take money or collect any other sensitive information, so there's not much risk as long as you don't use the same password for every site you log in to.

          Here's one of my sorta musical verses, though I have a lot more on weird critters and weird words than on musical subjects. (House style is to put the defined word in bold type.)

          With sesquipedalians besotted,
          I'd never declare, "This note's dotted"
          (Or use slow — I say lento).
          So accrescimento
          Adds time to the note I just jotted.


          • #7
            C4 is right in the middle of the keyboard. Larger pipes are to be found in the bass section and even then their size and length depends on whether we have an 4', or 8', or 16', or 32'....