How to approach playing rhapsodic passages against left hand in Chopin prelude#24? Does anybody play it and know how to learn it in a proper way? I have seen one score edition which suggests to split notes in the right hand in 2 or 3 notes inside a group against every single note in a left hand. Are there any other ways and exercises to learn it effectively?
I can give you a few suggestions.
Firstly the obvious ones - ask your teacher and listen to some online recordings of the piece. That should give you a feel for what you are aiming to achieve.
Now what you need to do is analyse the bars which you are having problems with. I take it that you mean the runs such as in bar 14.
So lets look at bar 14. You have 27 notes to play in the right hand. I would suggest that you play 13 in the first half of the bar and then 14 in the second half of the bar. That's certainly how I would set about learning it, squeezing in an extra note in the last semiquaver (16th note) of the half bar. Same thing for the second half bar but squeezing in two extra notes.
Work on the that until you can play the notes easily (both hands at once, obviously). After that you can look at trying to smooth out the run so that it goes more evenly and the notes no longer align with the left hand. There's not too much to do there because it is often the case with these runs that they speed up at the end, so aim to get the first 23 or 24 notes pretty even and just speed up through the last ones to the climax of the run, on the top F. I've heard it played that way, and its very effective.
This will take a lot of time and a lot of practise. But you are trying to play a piece of some difficulty so you should expect to have to work at it.
There are many YouTube videos about it. You may find what you need at http://www.pianosociety.com/threads/chopin-prelude-op-28-no-24-help.4420/ It is a good website for other things as well.
Look for waypoints throughout the measure where the hands will certainly want to coincide. You want the downbeat of each beat certainly, perhaps another subdivision if that makes sense. When picking the note to match with the beat, look for something that makes harmonic sense.
Then you can practice the smaller sections like you would any polyrhythm. Alternate right hand and left hand in rapid succession until you can flow them together at once.
The whole point of these passages is that the hands don't "fit together". Each goes its own way.
Once you have settled on the basic tempo, (and this isn't a speed competition - "Appassionato" doesn't mean "Presto"), when you come to one of the "rhapsodic" bars play the left hand more or less "a tempo," and then let it wait for the right hand to finish doing its thing. Don't try to slow down the left hand, and/or speed up the right hand, to fit all the notes into some mathematical relationship with each other.
If your hands can play independently, the hardest part is likely to be the chromatic scale in double-thirds on the last page, which is written "in time", and not "rhapsodic".
If your hands can't play independently, that is what you need to work on, before you attempt this prelude. Invent your own technical exercises where each hand is doing something completely different (e.g. playing in a different key, a different time signature, and a different tempo). Once you can do that, most of the problems with this prelude will have gone away.