Wednesday, February 24, 2016

principles of organ registration

You've managed to "survive" all of those knobs and buttons for several weeks now as a pianist trying to deal with an organ (and if you haven't, see my earlier series). Now what?

Now we explore combinations of stops that are often used together because organists have found them to be pleasing and useful. For instance, the old "principle chorus"

In the last series, we introduced the families of organ sound: foundations, flutes, strings, mixtures, reeds, and mutations. A principle chorus is basically a group of all the principle (or foundation) stops on a division (keyboard) of the organ. Usually what that means is you would draw the 8 foot, 4 foot, and 2 foot foundations, and, for good measure, you might add a mixture stop to the combination. This is a combination that is used most often for hymns. As I enjoy variety, and my congregation does, too, I would advise against deploying all of these stops all of the time for hymn playing. Depending on the size of the congregation, the building, and the intensity of the hymn's message, you may use only one or two of the stops for a quiet verse, or the 8, 4, and 2, without the mixture. What you probably do not want to do is use the upper stops without the ones below it. In other others, the 8 by itself, but none of the others alone, is OK. The 8 and the 4 alone, but not the 4 and the 2 alone (without the 8). Since stop jambs are often built vertically so that the larger numbers are toward the bottom (i.e., the 8 foot stops), you can imagine that it would not be possible for a column to hang suspended in the air without a connection to the ground. Thus, the higher stops cannot be used without using the ones below them, in order--8, then 4, then 2, then mixtures, cumulatively.

Sometimes this combination includes the 2 2/3 mutation stop as well. In which case, you will want to use all of the following foundations: 8, 4, 2 2/3, and 2.

The organ is an instrument which reinforces overtones. That acoustic phenomenon means that a sounding pitch includes not only the note we are playing (known as the fundamental) but also several higher frequencies, the first of which is the octave above. The second "partial" (overtone) is a fifth above that, and next the succeeding octave. If you include the fifth-sounding mutation stop in your mix, you reinforce that second overtone. The remaining octaves above the original sounding pitch (the 8foot stop) reinforce the first partial of the stop below that. The mixtures, comprised as they are of usually 3 to 5 pipes, sounding octaves and fifths above a single note, also reinforce overtones. The result is a full, rich sound. Remember, if you have a smallish organ, you can always borrow any missing stops by coupling the manuals together.

You might also want to try creating choruses of other stops. A flute chorus, for instance (8, 4, and 2) might sound very nice. You might do just as well with only the 8 and the 4. This is a nice, soft combination. You aren't as likely to be able to create a chorus of strings on any but a fairly large organ (Faith's only has 8 foot strings), though you could try using the super couplers (swell to great 4) in order to have that upper octave sounding on the great along with the great's 8 foot strings.

Mixtures and mutations are not good except in combination with other families, though as I discovered last year, combining the tierce and the nazard creates a very odd little sound known as a sesquialtera, which you could use to play a melody for a solo piece. You are also not likely to have enough reeds on a small organ to build a full chorus, but if you do, give it a try. If they are in tune, count that a miracle!

You could also try choruses in combination. What happens when you add a chorus of flute stops to a chorus of foundations? Probably not much. On a neo-Baroque organ such as the one at Faith, the flutes are so much softer than the foundations that it doesn't add much in the way of volume. However, if you have fairly abrasive foundation stops, the flutes might mellow them somewhat. Flute stops have wider mouths than foundation pipes, and are richer in overtones. Using 8 foot flutes and an 8 foot principle would mean you are combining different scales (basically widths) of pipe on the same pitch. Early manuals on organ registration consistently warn against doing this, but that was mostly because there was only so much air to go around, and dividing them up among weaker pipes was unnecessary waste for little effect. On a modern organ it won't make a difference.

Before we go let's talk about an exception to the idea of building consistently from the bottom. Suppose you employ the 8 foot and 2 foot foundation (or flute) stops without the 4 in between? That would create a gap in the overtones, and indeed, is known as a gapped registration. Many organists warned (and warn) against using gapped registrations, although I happen to like them. They give a somewhat quirky, intriguing sound. I wouldn't overuse them, however, and I wouldn't use them for hymn singing but only for solo pieces. Ever the experimenter, I noticed in listening to old recordings that there was a period a couple of years ago when I was experimenting with gapped registrations in the pedals. That got some really interesting results!

And that's just it. Once you have some general principles of how organ registration works, you can try a number of things yourself to get to know your particular, unique instrument. Even a 30 rank organ must have at least a thousand combinations!

This week on : we celebrate Samuel Wesley's 150 birthday (that's today!), a musical mystery deepens, I have my own Oscar speech ready, and we say goodbye to February (but not, I should note before we got another nice snowstorm! Stay safe, wherever you are!)

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