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    Mixtures

    I have a question about mixtures.

    Do all of the ranks of a mixture break together, or do individual ranks break separately, i.e., on different places in the compass?

    Thanks

    Tom Beck

    #2
    Originally posted by tbeck View Post
    I have a question about mixtures.

    Do all of the ranks of a mixture break together, or do individual ranks break separately, i.e., on different places in the compass?

    Thanks

    Tom Beck
    I really do not understand what you are asking. But you can get fairly precise descriptions of what a mixture is by going to the mixture entry in any 'Dictionary of Organ Stops' or Wikipedia or search engine. There is no one way to make a mixture, and I'm pretty sure that just about anything that is possible has been tried at one time or another. HTH

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      #3
      Originally posted by tbeck View Post
      I have a question about mixtures.

      Do all of the ranks of a mixture break together, or do individual ranks break separately, i.e., on different places in the compass?

      Thanks

      Tom Beck
      on a pipe organ, all of the ranks break back together at each break point. the ranks will alternate between unison and fifth-sounding at each break. Hope this helps. I can go into more detail if you wish.

      Rick in VA

      Comment


        #4
        On various electronic organs I've observed different ways of handling the breaks. Certain old analogs might start with something like 1-1/3' + 1' + 2/3' + 1/2' in the bottom octave. At the first break, which might be at C2, the highest pitch would end, and a lower pitch would be introduced below the 1-1/3, perhaps a 2' (so as to maintain the balance between unisons and fifths). That composition would go on for an octave, and then at C3, the next highest pitch (which at that point would be the 2/3') would end, and a new one introduced below the 2', probably 2-2/3'. At the next break (C4), the next highest pitch would end, and a new one would be introduced below the 2-2/3. Do you see where this is going?

        Now that was a typical old Baldwin that did that, but other analog organs would use a similar scheme. Digitals can of course do it any way the designer desires, but the concept is similar. At the break points, you lose a high pitch and gain a lower one. The pitches in between will probably continue unchanged until the next break point.

        This is of course quite audible when you listen to the mixture by itself, but the goal is to have a fairly consistent sparkle from bottom to top, and this requires using higher partials in the lowest octaves. As you go up the scale, these same partials cannot continue, as they would soon become so high pitched as to be inaudible. Or in pipe organs, would become so tiny that they would be impossible to tune.

        There are other types of mixtures that have a different system altogether. For example, a mixture call a "cymbel" is sometimes just a one-octave long set of pitches that repeat over and over as you go up the keyboard. So the lowest C plays exactly the same thing as the top C. This type of mixture might be very inexpensive, as you only need 36 pipes to do a complete Cymbel III for the full keyboard range. It gives a distinct sparkle that is different from regular mixtures, but quite nice in its own way.
        John
        ----------
        Church: Allen MDS-45 with Allen MIDI-DIVISION-II expander
        Home: Allen Renaissance R-230 with expanded four-channel audio and MIDI-DIVISION-II
        Shop: Bunch of organs in varying conditions, some good, some not...
        Half of an incredible two-man organ service team -- servicing all the major digitals in Arkansas churches
        https://www.facebook.com/pages/Birds...97551893588434

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          #5
          Thanks, all for the responses.

          The reason for my question is that I'm working with a GrandOrgue organ definition file (ODF). There is a property called HarmonicNumber, which is used by GO when a temperament other than the original is used. The harmonic number is a multiple of 64. An 8' stop would have a harmonic number of 8. A 4' stop =16, 2' = 32, etc.

          In the case of a mixture stop, which has several pitches, I'm not sure what the harmonic number should be. The harmonic number can be assigned to an entire rank or on a per-pipe basis. So if you created a mixture rank from individual stops, you can easily determine the number. But if a sample contains all of the ranks for one note in one sample, I'm not sure how to handle that. I guess if I can figure out where the mixture breaks then I could use one harmonic number for that range, but I'm still not sure.

          Tom

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            #6
            Originally posted by VaPipeorgantuner View Post
            on a pipe organ, all of the ranks break back together at each break point. the ranks will alternate between unison and fifth-sounding at each break. Hope this helps. I can go into more detail if you wish.

            Rick in VA
            Actually, unless it is a really large mixture, only one rank actually breaks at the break point. What happens is all the ranks shift over a set of holes at each break point, which keeps the shortest pipes on one "side" of the mixture and the longest on the other. This looks better, and makes it easier to get to the pipes for tuning. To put it another way: if a 2' pitch carries clear through on a particular mixture, there is no reason you could not leave the 2' rank in the same row of holes through the entire compass. It would just look funky, and maybe make those pipes hard to get to at certain points if the pipes on both sides of it are longer. Instead, that 2' rank gets shifted over one set of holes at every break point.

            I'm not sure if this verbal description will be adequate, but it's the best I can come up with at the moment.

            Comment


              #7
              Sounded like a good description to me, as that is exactly what happens.
              Mike

              My home organ is a circa 1990 Galanti Praeludium III, with Wicks/Viscount CM-100 module supplying extra voices. I also have an Allen MDS Theatre II (princess pedalboard!) with an MDS II MIDI Expander.

              Comment


                #8
                I was pretty sure that only one rank of a Mixture breaks back at a time, but I was not aware of the physical ramifications of it on the Toe Board--it makes sense, though.

                David

                Comment


                  #9
                  Originally posted by Schnarrwerk View Post
                  Actually, unless it is a really large mixture, only one rank actually breaks at the break point. What happens is all the ranks shift over a set of holes at each break point, which keeps the shortest pipes on one "side" of the mixture and the longest on the other. This looks better, and makes it easier to get to the pipes for tuning. To put it another way: if a 2' pitch carries clear through on a particular mixture, there is no reason you could not leave the 2' rank in the same row of holes through the entire compass. It would just look funky, and maybe make those pipes hard to get to at certain points if the pipes on both sides of it are longer. Instead, that 2' rank gets shifted over one set of holes at every break point.

                  I'm not sure if this verbal description will be adequate, but it's the best I can come up with at the moment.
                  Should not the compensation mixture (wow what hard thing to say to someone) increase in rank count downward and diminish in volume going up?
                  Instruments:
                  22/8 Button accordion.

                  Comment


                    #10
                    Originally posted by Schnarrwerk View Post
                    Actually, unless it is a really large mixture, only one rank actually breaks at the break point. What happens is all the ranks shift over a set of holes at each break point, which keeps the shortest pipes on one "side" of the mixture and the longest on the other. This looks better, and makes it easier to get to the pipes for tuning. To put it another way: if a 2' pitch carries clear through on a particular mixture, there is no reason you could not leave the 2' rank in the same row of holes through the entire compass. It would just look funky, and maybe make those pipes hard to get to at certain points if the pipes on both sides of it are longer. Instead, that 2' rank gets shifted over one set of holes at every break point.

                    I'm not sure if this verbal description will be adequate, but it's the best I can come up with at the moment.
                    Technically, what schnarrwerk said is true...to a point. It somewhat depends on the base pitch of the mixture and how many break points there are in the compass (how many breaks over how many keys).

                    Let's start with his hypothetical 2' based mixture and we will assume 3 breaks in total and 4 speaking pipes per note. at key number one the composition would be: 2', 1 1/3', 1', 2/3' (C, G, C, G). at the first break the low 3 ranks 'move over' to the next forward rows and the 2 2/3' pitch is introduced. at the next break point the low 3 pitches 'move over' and the 4' pitch is introduced, and at the final break point, again the low 3 pitches 'move over' so the composition becomes 8', 4', 2 2/3' and 2'.

                    This doesn't hold true with a high-pitched mixture like a cymbel or sharff because as some points the pipes become to short to be practical to tune (conventionally, most mixture sets don't have pipes shorter than the top pitch of a 2' rank (which is approximately 3/16" in theoretical length) so while the 'move over to the next row' holds true at the first couple of breaks, some of these mixtures have repeating pitches that are reintroduced so that the tuneability of the mixture remains. There are cymbel mixtures that I tune that have 6 or 7 break points and the base pitches drop out after the first 3 breaks and then are reintroduced as the notes ascend on the keyboard.
                    The idea of keeping one pitch on one row thruout the compass is only possible using electro-magnetic pipe valve units - one for each pipe like the early Wicks organs. Most mixtures are mounted on toeboards with channeling so that all pipes speak from a common valve which was the only way to do mixtures on mechanical action organs and electro-pneumatic organs. so there are practical reasons for how and why mixture pipes are arranged the way they are.

                    Rick in VA

                    Comment


                      #11
                      My example was just a "simple" mixture chosen for illustrative purposes. There are, of course, all manner of mixtures out there with all sorts of break and pitch schemes.

                      You might rethink your last paragraph a bit. The only reason to use a separate valve for each hole is if one is "borrowing" a separate stop (Doublette or Larigot, say) from a mixture.

                      Comment


                        #12
                        Originally posted by Schnarrwerk View Post
                        My example was just a "simple" mixture chosen for illustrative purposes. There are, of course, all manner of mixtures out there with all sorts of break and pitch schemes.

                        You might rethink your last paragraph a bit. The only reason to use a separate valve for each hole is if one is "borrowing" a separate stop (Doublette or Larigot, say) from a mixture.
                        I included the problem of individual valves under each pipe instead of one valve for each group of pipes (per note) because it has been a common practice of one particular builder. I would not recommend using that method (one valve per each pipe) and would also not recommend extracting a larigot or other off-unison stop from a mixture. Placing mixtures on channeled toeboards (thus one valve per note rather than one valve per individual pipe) is far better as the pipes come onto speech together and stay better in tune with each other.

                        Rick in VA

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