Here we enter a whole different realm of keyboards - organs are not, I repeat, not, modified pianos - the only commonality is that they happen to both have 'piano-keys'.
Please refer to this Wiki link for the history of the organ (from pipe organs to console/spinet to present). I intend here to focus mainly on the all-time much-copied Hammond B3 and the evolution of the current digital organs and emulators.
From a purist point of view - no amount of digital technology can ever hope to emulate the sound of a real tone-wheel organ - nothing (in the same vein as the Rhodes piano) - the "Hammond" sound is unmistakeable to the trained ear, and to anyone who has ever had the pleasure of playing a B3 (or similar from the Hammond family). Most interestingly, the sound of the B3 came about mainly due to design flaws - keyboard clicks and pops, hums, growls etc.
There are many sites on the net which cover the evolution of the B3, as well as it's masters - see right hand side bar for links to the B3 Masters.
Here's an outline of the history of the Hammond Organ and also History of the B3
Playing Technique : 'piano' versus 'organ'
As I stated earlier - there really is no comparison. Here I will outline the major differences with respect to organs:
- no sustain when the keys are released - necessitating in modified playing technique
- no attack/velocity/sensitivity - the note is either 'on' or 'off' no matter how hard it is struck
- expression controlled by the right foot - commonly referred to as the 'volume' pedal
- hands also responsible for controlling drawbars and presets in order to modify sound and timbre
- foot operated pedals in order to provide a bass line or countermelody
So, if you can already play a piano-type keyboard, you're well ahead in the learning curve for an electronic organ - it's just a matter of adapting your physical ergonomic approach i.e. transitioning from note to note, or chord to chord; learning the pedalboard and the expression pedal, and mastering playing on two, staggered keyboards.
If you don't already play a piano-type keyboard, I would definitely not recommend starting on organ - seriously, unless you intend to solely focus on the organ. Virtually every technical rule for piano technique is broken when you approach an organ - even the fingering styles, glisses, and wipes are totally anathema to 'serious' professional pianists - on a personal note here, my piano teacher almost had a meltdown when she discovered I was playing the organ routinely, stating that it would ruin my classical technique. It didn't, and here I am! But, I had 13 years of classical training under my belt before attempting the organ, and that really does account for a greater ability to be able to switch from one mode to another, without detriment to either.
By far the most difficult technique for me to master was the use of the expression pedal - after learning 'legato' pedalling on the piano, one's right foot automatically goes into 'legato' mode - with the resulting sound from the organ becoming very strange and distorted!
One final comment here re B3 emulators - current digital synths from Roland and Korg have many "B3" sounds built in, and there are also many patches available on the net for import into your keyboard i.e. B4 Real is a popular one - some even incorporating key clicks and growls; also available are drawbar plug-in modules (modified MIDI controllers), or complete software packages such as those available from Native Instruments
A good friend of mine in Cologne, Germany - brilliant pianist, electronic keyboard wizard and B3 purist was once asked what keyboard he used to reproduce the unique sound of the B3........his response was ...."errrm.....a B3 !"......you can check out his site here - Noel Stevens
bravenet.com