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  • On the fly perfect chord tuning

    I shouldn't stay up this late thinking. Tonight I spent too much time thinking about intonation and differences between a fixed pitch instrument like the organ and more flexible pitch instruments (flute, violin, trumpet, etc.). Anyone who spends very much time learning about tuning quickly learns that equal temperament (or any temperament) is a series of interval compromises so that the instrument sounds pretty good regardless of the key a piece is played in.
    One of the things that I like about attending concerts of fine musical groups is that the different members can adjust the pitch of their separate instruments (or voices) so that the overall chord is perfect. A brass fanfare is amazing live with a good group because all of the chords are way more perfect than a fixed pitch instrument can ever be.
    We now have digital and virtual instruments that can be set at various temperaments (instantly) with the click of a button (or the adjustment of a setting).
    So, why don't we have a "perfect chord" or "chord tuning" option on our digital or virtual organs that detects the chord being played and adjusts the pitch of the different parts of the chord so that it is perfectly (or nearly perfectly) in tune?
    I would imagine that it is possible for a computer to detect the chord being played and adjust the pitch of some of the notes in the chord in a few milliseconds. I've seen some keyboards that determine the chord from the notes played and show the chord name on the screen.
    Maybe the logic could be: equal temperament is used for individual notes and for the tonic of three-or-more-note chords. The notes in two-note chords get moved together or apart so that everything stays close to equal temperament but the interval sounds clean. The other notes in three-or-more-note chords would then be adjusted so that the chord is in much better tune. I would imagine that there are some chords (or intervals) that would sound much better in equal temperament (highly dissonant chords maybe).

    A few caveats:
    I know that the notes, ranks, or samples in digital or virtual organs are often slightly out of tune with each other so that the ensemble is better for the organ. I'm not sure how this would be addressed with the "perfect chord" option.
    I also know that some organ repertoire was specifically written to take advantage of the sweetness and/or dissonance of different keys in a well temperament. In this case "chord tuning" wouldn't be used.
    I also know that adding this to a digital or virtual organ would make it so that it is does not sound like a fixed intonation pipe organ. I think it might make it sweeter, but I'm not sure. Maybe it would make it sound too sterile.
    I think I remember reading somewhere on here that pipe organs occasionally do something like this (on some ranks) because the speaking pipes might interfere with each other.
    I don't have the slightest idea about how I (or someone) would implement something like this.
    Sam
    Home: Allen ADC-4500 Church: Allen MDS-5
    Files: Allen Tone Card (TC) Database, TC Info, TC Converter, TC Mixer, ADC TC SF2, and MOS TC SF2, ADC TC Cad/Rvt, MOS TC Cad/Rvt, Organ Database, Music Library, etc. PM for unlinked files.

  • #2
    You'll be happy to know that this very thing has indeed been done! I just now tried to find the reference on line but failed to locate it. I'm almost certain that it is Content Organs that offers (or once did) a feature that was called "live adaptive tuning" or something like that. Where I saw it, there was a detailed explanation of the process, much as you imagined it above, and there were even audio clips of various organ pieces being played with and without this adaptive tuning enabled.

    As you suggest, the system was able to instantaneously analyze the combination of notes being played at a given moment, and within a few millionths of a second it would adjust the pitch of the notes in a chord so that they were mathematically aligned. There was even the ability to control the degree to which this "re-tuning" would be done, since some chordal dissonance is probably a good thing. Just as the intentional slight pitch differences among the ranks imparts some life, so does at least a little of the unavoidable inter-note beating of equal temperament. So you could have the system re-tune the errant pitches anywhere from 0% to 100% of what it required to bring them into perfect "just" or "Pythagorean" alignment in a chord.

    Where this system pays off is when large reed registrations are used in a fanfare, as you also mention. In a major triad, the third is pretty seriously out of tune with the true mathematical pitch needed for a perfect chord, and it really shows when the tones are reedy. Trumpet and trombone players instinctively apply subtle re-tuning as they play to minimize these errors in pitch, and this system gives the organ a similar ability to tune up on the fly.

    I wish I could find the write-up and demonstration of the system. I know it was on some manufacturer's website, and I just want to say it was Content, but I sure can't find it today. Perhaps it was another builder, or maybe it has been dropped as a feature. Maybe someone else has seen it and will remember how to find it.
    John
    ----------
    *** Please post your questions about technical service or repair matters ON THE FORUM. Do not send your questions to me or another member by private message. Information shared is for the benefit of the entire organ community, but other folks will not be helped by information we exchange in private messages!

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    • #3
      Thanks John. I'll have to do some more searching. Maybe I can figure out how to set it up on a virtual organ.

      I don't know how reliable this source is but it's an article about a pure tuned pipe organ. http://wmich.edu/mus-theo/groven/eg_orgel.html

      Johannus also has a LiveTune feature listed on most of their organs but I haven't found any info on it yet.

      There's also this link about Hermode tuning.
      Last edited by samibe; 07-04-2018, 12:15 AM.
      Sam
      Home: Allen ADC-4500 Church: Allen MDS-5
      Files: Allen Tone Card (TC) Database, TC Info, TC Converter, TC Mixer, ADC TC SF2, and MOS TC SF2, ADC TC Cad/Rvt, MOS TC Cad/Rvt, Organ Database, Music Library, etc. PM for unlinked files.

      Comment


      • #4
        Here is a video with a complete explanation and organ samples. This is in Dutch, but with English subtitles. I don't think this is the one I saw a few years back, but it does give comparisons between ordinary equal temperament and "Hermode" or computer adaptive tuning.

        https://www.youtube.com/watch?v=uHIA-DM3Wrs
        John
        ----------
        *** Please post your questions about technical service or repair matters ON THE FORUM. Do not send your questions to me or another member by private message. Information shared is for the benefit of the entire organ community, but other folks will not be helped by information we exchange in private messages!

        https://www.facebook.com/pages/Birds...97551893588434

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        • #5
          Thanks for the link, John. This is a really interesting concept. I found another link on Hermode tuning here: http://www.hermode.com/index_en.html

          This article mentions that the German organ builder Mitteldeutscher has made a pipe organ with Hermode tuning! The article says:

          Each pipe has a tuning device, controlled by a magnetic drive. A CPU controls these magnetic drives in real time, depending on the current harmonic situation.

          I would love to hear how this works, but unfortunately, there are no audio examples of this.
          Bill

          My home organ: Content M5800 as a midi controller for Hauptwerk

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          • #6
            Bill,

            Does your Content M5800 perchance have "Hermode" as one of the selectable temperaments? I'm almost dead sure that it was on the Content Organ website I first heard about this concept several years ago. Not sure that they were putting it on all their organs, or if was an extra-cost option.
            John
            ----------
            *** Please post your questions about technical service or repair matters ON THE FORUM. Do not send your questions to me or another member by private message. Information shared is for the benefit of the entire organ community, but other folks will not be helped by information we exchange in private messages!

            https://www.facebook.com/pages/Birds...97551893588434

            Comment


            • #7
              John,

              Here is the description from the owner's manual:

              Following historical tunings are available:
              1. d’Alembert
              2. Bach
              3. Equal Temperament
              4. Kirnberger
              5. Mean Tone
              6. Pythagorean
              7. Sauveur 1701
              8. Vallotti & Young
              9. Werckmeister
              10. External (reserved for future developments)

              I tried temperament 10 and clearly it is set to something, but I have not figured out what it is exactly. It does not like the flat keys very well. When I have some time I will see if I can identify it and then I will post my findings. I wonder if "future developments" could include the possibility of adding Hermode tuning. I will have to send an email to Content. I will let you know what I find.

              Take care,

              Bill
              Bill

              My home organ: Content M5800 as a midi controller for Hauptwerk

              Comment


              • #8
                Interesting discussion, but I don't see how a computer can make a perfect correction based solely on the notes being played. Outside of the world of equal temperament schemes, G# and Ab are different pitches and string players would play them as such. So if you are playing on a keyboard Ab, C, and Eb, that's an Ab major chord, but it's also a G#major (G#,B#,D#), and Cminor+5 chord, and if tuned perfectly, they'd be different from an Ab major chord, would they not?

                For early music, with a strong tonal center, it's doable, but If you look at heavily chromatic music from Romantic era, such as Franck or Vierne, you'll commonly see repeated notes that are notated one way in one measure and a different way in the next, e.g. a C## (double sharp) becomes a D natural. On the keyboard, they're the same note, but in the harmonic context of the piece, they are not the same and are correctly notated differently. So, for a computer to perfectly tune each and every chord, it would have to analyze the harmonic progression of the piece, not only looking at what came before, but also on what's coming next.
                Last edited by Admin; 07-04-2018, 09:36 AM.
                -Admin

                Allen 965
                Zuma Group Midi Keyboard Encoder
                Zuma Group DM Midi Stop Controller
                Hauptwerk 4.2

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                • #9
                  Admin, you make some valid points. There is a good explanation of how Hermode tuning works on their website under the "History of Tuning" tab. (http://www.hermode.com/history_en.html) They have some excellent audio examples to demonstrate the system.

                  There are some comprimises that the system seems to make in certain situations. One example they give is when playing a dominant 7th cord. From the website:

                  One of the program variations of Hermode Tuning tunes the seventh in dominant-seventh-chords to the so-called “natural seventh”. This sounds great, but due to the deep pitch of this seventh, some chord sequences .... shouldn’t be played legato.

                  They explain earlier in the article that the decision for how to tune a note is at the "note on" point.






                  - - - Updated - - -

                  Following up on John's question, "Does your Content M5800 perchance have "Hermode" as one of the selectable temperaments?

                  Temperament 10 is
                  d’Alembert, so it appears twice. I intend to contact Content to see if I could have Hermode added in this spot.

                  I also researched d'Alembert's system. It is a modification of Meantone. His objective was to increase the number of "good" thirds. It does do this, but it sacrifices the keys of C# (Db), Eb, Bb, and F. Like I said in my previous post, it does not like Flat keys very well. That being said, it sounds wonderful in most of the other keys.



                  Bill

                  My home organ: Content M5800 as a midi controller for Hauptwerk

                  Comment


                  • #10
                    About 8-10 years ago or so I had a new Johannus 397 organ that came factory equipped with 12 different tunings, most of which were quite nice to play around with.
                    The least liked I must confess was the Equal Temperament, the one most universally heard in North America all all music events, whether church or concert hall.
                    The Rembrandt also had a tuning (#13) that you could set up yourself. We toyed around with the so-called concept known as the "circle of fifth" and came up with a setting that had very nice sounding chords in almost all of the sharps and flat keys. We heard chord combinations never heard before, difficult to describe, but it seemed as if the music came alive.
                    Changing the half step transposer settings added another dimension to the overall projected sound and even more so when the pitch control was adjusted to get in between those half steps.
                    A major living accomodations downsizing made me sell it to a church and I bought a 2m Sweelinck with just Equal, Werkmeister and Meantone, also very useful. Our pitch is set at 425 and yes, every chord sounds different than what your ears are accustomed to than Equal at 440. Yes, I miss my Rembrandt custom tuning capability.

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                    • #11
                      Originally posted by voet View Post
                      One example they give is when playing a dominant 7th cord.
                      I was assuming that the system was trying to deal with the enharmonic differences, but I realize now that it's just concerned with adjusting the tunings of intervals. Still, I wonder how the system fares with more complex chords found in music after the classical era, especially if there are caveats for a dominant seventh.

                      The differences in the examples was very subtle (to almost to the point of non-existence) to my ears, and I'm not sure that I would have picked the Hermode tuning as sounding better if it hadn't been suggested that it did.
                      -Admin

                      Allen 965
                      Zuma Group Midi Keyboard Encoder
                      Zuma Group DM Midi Stop Controller
                      Hauptwerk 4.2

                      Comment


                      • #12
                        It has been fascinating trying to research this a bit. Hermode tuning seems to try to keep everything as close to average equal temperament as possible when it adjusts the intervals. The idea here is to mitigate pitch drift (through a series of chord progressions) and make the adjustments small regardless of which chord comes next. They also have a pitch deviance cap (something like 20 cents) so that really dissonant intervals don't get moved so much that they are no longer the correct interval. It also looks like there are several ways to implement pure on the fly chord tuning. Some allow a little pitch drift. Others keep track of what chords have been played and attempt to keep the average pitch from straying too far. Most seem to constrain the pitch but allow all of the notes in the chord to move a bit.

                        Here is a short video of a Hermode pipe organ that I found this morning. I wish it showed more playing.
                        Sam
                        Home: Allen ADC-4500 Church: Allen MDS-5
                        Files: Allen Tone Card (TC) Database, TC Info, TC Converter, TC Mixer, ADC TC SF2, and MOS TC SF2, ADC TC Cad/Rvt, MOS TC Cad/Rvt, Organ Database, Music Library, etc. PM for unlinked files.

                        Comment


                        • #13
                          I find this thread really interesting.

                          One of the advantages attributed to this flexible system is that it can more closely match the pitches of string players or vocalists. When I directed choirs, I had them sing a capella a lot, even when learning a new piece. So many problems are alleviated then choirs sing this way--intonation, tuning, balance and blend. Now that I have an organ that can play in different temperaments, I am exploring the various tunings and trying different literature.

                          I noticed that there are also some YT organ recordings in different tunings.

                          - - - Updated - - -

                          Sam,

                          Thanks for sharing this. I agree, it would be nice to hear more of this organ.
                          Bill

                          My home organ: Content M5800 as a midi controller for Hauptwerk

                          Comment


                          • #14
                            Or you could buy an organ manual with split sharps

                            https://en.m.wikipedia.org/wiki/Split_sharp

                            Some Kontakt instruments have a Diversi mode where the individual notes of a chord are distributed to different instruments within the ensemble. I'm sure that some scripting could be used to adjust the pitch of the individual notes in real time to achieve the required outcome.

                            You could also set up an arrangement where you could subtly bend individual notes within a chord using polyphonic key pressure. This would challenge your technique

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                            • #15
                              Obviously this is not a burning issue in the minds of most organists, and most of us are perfectly content to play instruments in equal temperament. Today's digitals even intentionally add some beats by detuning some ranks or some audio channels, or even offsetting the pitches of octaves within the same rank. So the assumption seems to be that we sort of like random beating in our chords.

                              After all, one of the complaints sometimes lodged against the Hammond organ was the absence of beats in the intervals (since everything is sine waves, and all harmonics are synthetic, thus not going to beat against anything).

                              On my Allen R230 I have several temperaments available, and I find that certain of them have "perfect" tuning of certain chords. For example, "Just" intonation seems to provide 100% perfect intervals for C, F, and G chords, but almost any other chord is abominable. "Kirnberger" seems to be a compromise of sorts, with NEARLY, but not perfectly, clear intervals as long as you are playing mostly white keys, getting really raunchy only when you play a chord with two or more black keys in it.

                              Obviously, these historical tunings were devised to complement ONLY certain pieces of music, and are disastrous for a composition that includes intervals which are intentionally sour in such a temperament. Thus we have settled on the Equal Tempered Scale as championed by Bach (or so I've heard) because it allows one to play any piece of music in any key without being too offensive. But the argument could be made that certain pieces of music really "shine" when played in the temperament for which they were written.

                              The genius of Hermode is that it automatically adapts, faster than any human brain or ear can detect, to eliminate or at least minimize the beats in any interval or chord or combination of notes that one might play. This instantaneous re-calculation of the pitches of individual notes is equivalent to being able to switch instantly among all the available temperaments on your digital organ, plus many others than you don't have, in real time as you play, in order to maintain a consistently beatless harmony.

                              Listening to the examples given, I don't hear much to make me want an organ that can do this, but I do understand how nice it can be under some circumstances. When we listen to a brass ensemble playing, we know that the players are all listening TO ONE ANOTHER and constantly adjusting their pitches in a minuscule manner in order to make their intervals consonant. Hermode tuning makes the "pipes" in your organ as intelligent as the well-trained players in an orchestra or chamber ensemble.

                              To get a small idea of the improvement, you can put your organ into Kirnberger or Just mode and play some simple piece in the key of C that never gets off on the black keys. Marvel at the "purity" of the intervals, then do it again in Equal Temperament and you'll occasionally recognize a slightly dissonant interval that you'll wish you could "tune up" just a tad!
                              John
                              ----------
                              *** Please post your questions about technical service or repair matters ON THE FORUM. Do not send your questions to me or another member by private message. Information shared is for the benefit of the entire organ community, but other folks will not be helped by information we exchange in private messages!

                              https://www.facebook.com/pages/Birds...97551893588434

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