Super and sub octaves

[organmaniac]

Can anyone comment -
On a few local organs, I’ve noticed that the sub octave coupler will run out/stop at around the low F-sharp on the keyboard, and the super octave coupler will run out at the top F or so of the keyboard. Perhaps this is normal as those extreme notes from both ends won’t normally be required? I just find it odd that not every single note would be covered by these octave couplers.
Knowledge and comments would be interesting!

[toodles]

Without extra pipes, sub and super octave couplers would run out for the full bottom and top octaves respectively. AGO specifications indicate an octave extension on the top end for 73 notes total, but state that 68 notes will satisfy most organists, taking it to the top G. The specs indicate no extension on the bass end.

Making these extensions adds considerable expense to the cost of the pipework to the top end since it has to be done for every voice. It is almost prohibitively expensive on the bass end, since the bottom octave of a rank probably costs almost as much as the rest of the rank.

If an organ is well specified sub and super octave couplers are not needed to provide for creating full sound and the need for these extensions are not so important.

[crapwonk]

Interesting info from Toodles. I did not know that the AGO spec called for additional pipes to support the super coupler. Any pipe organs that I have played did not have any additional pipes added for a super coupler - no notes sounded above high C with both the super coupler and unison off. This generally did not cause a problem since I don't have a lot of music that actually goes above high C.

[organmaniac]

Toodles, many thanks - very informative!

[samibe]

Stopping at bass F# and high F seems interesting to me. Do these organs have a transposer? Also, you didn't specify whether your local organs were pipe or otherwise.

[Sathrandur]

Good info Toodles. But, like what has been said, does anyone really need the extra pipes for the very top octave? I would much rather have the extra pipes for suboctave couplers but, as said, it would be prohibitively expensive given the exponential nature of pipe dimensions (and thus cost).

[Hohl Flute]

Interesting last remark, Toodles. In the UK The Swell Octave coupler is an integral part of the Full Swell in a big romantic Harrison organ, yet in a Father Willis it completely overbalances the sound.

I actually find these couplers really effective for colourful combinations, especially if an organ as a particularly beautiful 4' flute. Use this with Octave, Sub Octave and Unison Off couplers and you begin to see why selective, sensibly planned unit organs DO have a place..... but not at the expense of properly balanced choruses...

[Leisesturm]

I actually find these couplers really effective for colourful combinations, especially if an organ as a particularly beautiful 4' flute. Use this with Octave, Sub Octave and Unison Off couplers and you begin to see why selective, sensibly planned unit organs DO have a place..... but not at the expense of properly balanced choruses...

You haven't done anything that cannot be done by a different organ with a particularly beautiful 8' flute and it's 2' counterpart. It was a slippery slope at best when the technology arose to make a single rank pretend to be more than that.

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Good info Toodles. But, like what has been said, does anyone really need the extra pipes for the very top octave? I would much rather have the extra pipes for suboctave couplers but, as said, it would be prohibitively expensive given the exponential nature of pipe dimensions (and thus cost).

I don't know how much they extend the bass octaves but big French organs nearly always had 'Octaves Graves'. And Dupre, Durufle, Vierne, and all the other noteworthy French Cathedral organist/composers made frequent use of them. 'Octaves Super' not so much. Cavaille Coll almost certainly obliged with fully extended bass octaves le coût soit damné.