Aug. 24, 2015

Calculating Stop Combinations, Part II

For example, let's say an organist has at their disposal a 2 manual organ equipped with 7 stops in the Great division, 9 stops in the Swell, and 5 in the Pedal, 21 stops in all.  Applying the formula 2 to the nth power minus one where n is 21, there are over 2 million possibilities, as follows:

X = 2 to the 21st power - 1  =  2,097,152 - 1  =  2, 097,151

Granted, the majority of these random combinations would sound horrid and find no use at all, but presuming that only 0.1% of them were worth storing on piston memory, that still leaves over 2,000 good sounding, useful combos, nearly 40 for every weekly worship service of the year.  The point being, even an unpretentious instrument of 21 stops still provides the artist organist an almost unlimited capability of beautiful landscapes of compound tones, all at his or her fingertips.

What if we had in front of us a very large instrument with 4 times as many stops, where would THAT takes us?  Let's find out ...

(con't in Part III)

 

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(con't from Part I)




Here's the formula:

X = 2 to the nth power minus 1, where

X = the number of possibilities, &

n = the number of stops

Using this formula (two to the nth power minus one) all the organist has to do to find out how many possible ways the stops of the instrument (or the couplers, as a group) can be used singly or in combination is to replace the exponent in the formula with the number of stops (or couplers) provided by the builder, and solve.