Reading the works of Bach, there's an unusual pattern I keep seeing. Consider, for example, the opening of the fugue from the infamous BWV 565:

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It constantly alternates between A, which doesn't move, and a lower note, which does move. Obviously this is a fugue, so this exact phrase appears again and again — but Bach seems to do this constantly, in just about every organ piece I've looked at. Sometimes the moving note is higher than the stationary note, sometimes it's lower. (In the toccata, one actually crosses the other at one point!)

Is there a name for this perculiar structure?

I know the general name for playing the notes of a chord sequentially is arpeggio. But this clearly isn't a chord, it's a melody. And there's always exactly 2 notes. And they always strictly alternate; never any more complex pattern. And one note stays stationary, and the other moves. And it only ever seems to move in fairly small steps, apart from the odd isolated jump. That all seems quite specific... like it should have a name. Also, as far as I know, only Bach does this. (Having said that, I've only ever tried to play Bach and pop songs, so...)

  • @Dekkadeci That answer just says it's called arpeggio. I'm not convinced that really describes this figure. – MathematicalOrchid Sep 24 '20 at 10:22
  • It doesn't matter whether any of its answers are correct - it asks pretty much the same question as yours, as far as I can tell. This website's precedent is to flag newer questions as duplicates and funnel viewers to older questions. – Dekkadeci Sep 24 '20 at 10:27
  • And the answer by RosieF there is correct in my opinion. I think the key concept is 'internal pedal point'. – Tim H Sep 24 '20 at 13:49

In the case shown, the "A" is termed an "organ point" or a "pedal point." (Usually pedal point is used for such an occurance in the bass, but I've seen it used for any voice.) It's a sustained tone with (usually) dissonant harmony being sounded against the sustained tone. It's the same case here but the tone is repeated alternately rather than being sustained; the harmonic effect is identical. The use of alternate repitition indicates that this fugue was probably originally conceived for violin or another stringed instrument rather than for the organ.


You might be looking for 'bariolage'. This term is more often used for string writing. As an aside, scholars are not in full agreement as to whether this is actually by Bach. One of the arguments is that the toccata 'looks' like a simple arrangement of an Italianate violin piece.

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