I know the pedals play notes and it's all finger-legato stuff up on the manuals
That doesn't scare me too much considering how much finger-legato I use in my piano-playing.
I'd like to know more about how you change the partials while keeping a piece going, and what partials to know which to choose.
Thanks!
Getting the pedals legato is even more interesting than getting the fingers legato... but I can assure you that it is perfectly possible to play legato chromatic scales, jumps, arpeggios, whatever with the pedals. Just takes practise (lots of it!).
I hadn't thought about it, but I do tend to hold my wrists rather high. And I do use some organ fingerings on the piano -- no surprise, since organ was my instrument, not piano, until I retired.
The variation in key force with a modern tracker with different stops shouldn't be all that great, although it may be there (depends on the instrument). Either coupling in another manual or coupling up or down an octave will change the key force. It is absolutely essential -- particularly with a tracker -- that one press the key down firmly and quickly; it must be either up or down, and this can take genuine strength on some instruments. With a tracker, anything in between is likely to result in somewhat odd noises (charitably put)! With electric or electro-pneumatic actions this isn't a problem at all, and key forces may be remarkably light, even for a very large instrument.
And Gustav Leonhardt was surely one of my real heroes!
I'm not quite sure what you mean about changing partials. Do you mean the choice of different stops -- what an organist would refer to as registration? Choice of registration is one of the things which one really must learn, if one is to play the organ at all well. It depends on the instrument, of course -- the small organ at the church which I currently attend has only two tone colours (principal (diapason) and flute) at a variety of pitches; very large organs may have a dozen or more, with variations on each, as well as differences in inherent volume and tone quality within the general group of tone colour. Then you also have the speaking pitch of the group of pipes (called a rank). They may speak at the same pitch as a piano (referred to as 8 foot), or as much as three octaves lower (16, 32, and 64 feet)(the length number is the actual length, in feet, of the longest diapason pipe in the rank; flutes are only half as long, and reeds may be much shorter) or as much as three octaves higher (4, 2 and 1). Then there are mutations, which speak a fifth or third higher (or, very very rarely, lower) than the piano -- the usual ones are 2 2/3 and 1 1/3, but there are others. Then you have mixtures, in which two or more pitches speak at once. The choice is mind-boggling! Judging which combination of stops to use where is very much part of the art of organ playing!
And composers are rather vague on the subject, for the simple reason that each organ is different and what may work splendidly on one may be either impossible or a complete catastrophe on another.
As to changing stops in mid stream, there are two fundamental approaches -- one is to have one sound quality set up on one manual, and another on another manual (or the pedal). This enables very fluid changes by switching manuals as you go along, and also enables one to play a solo line on one manual with an accompaniment on another. Sometimes a certain amount of contortion is required, as it is sometimes necessary to use two manuals simultaneously with one hand, but fortunately that is rare! The second is to actually change the stops drawn on a particular manual. Again, there are two ways to do this -- if it is just one or two stops which need to be drawn or retired, a lightning jab with one hand or the other will suffice; no more difficult than a huge jump on a piano. However, if it is a major change, you hope that your instrument has a combination action, with which you can preset certain groups of stops to correspond with manual buttons or toe studs -- then all you have to do is hit the right button at the right moment, and presto chango. Nothing to it.
(Some organs have a "crescendo" pedal, which automatically draws additional stops as you depress it -- never found on trackers -- and some organs also have a "sforzando" button or stud, which draws pretty much everything including the kitchen sink when you hit it; to be used with extreme caution)
There is a third approach: get your page turner to do it. This is risky, unless your page turner is a real musician...