Nitpick:
Leslie speakers don’t produce reverb, they produce vibrato.
Reverb is what you hear when you yell in a large empty hall and the echo reverberates back at you.
Vibrato is a tremulous or pulsating effect produced in an instrumental or vocal tone by minute and rapid variations in pitch.
Nitpick x 2: they produce both vibrato and tremolo, the latter being a rapid change in volume.
I dug up a list of rhythms for the Sideman, which is a standalone Wurlitzer beatbox of gargantuan proportions. I recall seeing these rhythms on organs:
Rhumba
Cha Cha
Tango
Samba
Beguine
Metronome
Bolero
Shuffle
Waltz
Western
4/6 March
Fox Trot I and II
Basically all the beats a swingin’ bachelor needs to woo the ladies!
http://totallyambush.co.uk/2008/06/15/analogue-dreams-1959s-wurlitzer-sideman-rhythm-machine/
With an electric/digital piano you can tap into the seemingly infinite supply of piano music. Not so much so with an organ. Not that there’s not a rich tradition of organ music, it’s just more of a niche than manufacturers anticipated, I think.
I was expecting a thread about biotech, I was all set to post links to articles about organ printing and tissue engineering and why someday artificial hearts may not be needed,
But upon opening the thread I heard the music about what it’s really about.
You’re right.
:shrug: Whatever you say. 
IANA engineer, or a physicist. They said it was reverb; I took their word. I used the effect, whatever it is, often quite a bit. AAMOF, doesn’t it say reverb on the switch? It’s been several years since I last was near a Leslie-equipped organ, so I could be wrong, easily.
I wrote a response to this the other night when I was sleepy, and apparently closed it without posting. Having the sounds on a computer ain’t the same as making them. I know of few musicians who consider eliciting the sounds from any sort of machine to be equivalent in satisfaction with using their own hands and feet to play an instrument (or mouths, for those who play wind instruments).
For me, there is no music so satisfying as what I can create with an instrument - or at least, none more so. I just recalled that there is some music - especially live - that is nearly as enjoyable (a short list, but it’s there) to listen to as it is to create. I don’t say it’s impossible to find people who could get equal satisfaction from using a computer, mixer or other sound generator to make music, but I do think that a poll would show such people to be a decided minority among musicians. There’s a big difference between those who took music lessons when they were kids because their parents insisted, or they just thought they might like it, and those of us who find it hard to walk by any instrument we can play.
And I suppose I should be careful to include singers. Those who really have a Voice, and a matching passion, also should be counted as musicians.
I don’t know if I buy that — after all, as you say, there is also a rich tradition of organ music: particularly in church. I wouldn’t call church-going people an “unanticipated niche.” Organs were also used as accompaniment to silent movies.
Besides, there was a whole passel of organ music in the 1950s. It was at one time a very popular instrument in its own right. Piano had its heyday fifty years before with ragtime, and everybody owned a piano or listened to piano music, but in the 1950s, the organ was more mainstream.
The leslie system is includes elements of several effects and is quite unique. The rotating speaker and/or baffles causes the sound to travel in different directions and take different paths to a listener’s ear, a change that usually happens several times per second. It’s not just vibrato, it’s not exactly reverb although echoes happen; it has some phasing elements and it is more effective in stereo than mono because each ear hears something a little different. The directed sound also causes the frequency spectrum of a held tone to vary, a little like a weak wa-wa.
One of the synthesized beats I remember was BOSSINOVA
Ahhh, I see you grew up in Dayton, Ohio too?
I’m not quite sure what you’re getting at with this. When I say I can download sounds, I mean the raw notes and data required to play my 88 key digital piano (a physical instrument) with whatever sounds I desire. I play it just like a piano, it feels like a piano under my hands and sounds like a piano if I want it to, but it can also sound like various different settings on a hammond organ or anything else people have developed sounds for. The Roland organ module connects to the keyboard and allows you to have control over the organ sounds using draw bars etc. There is really no difference between doing this and using a dedicated electric organ other than that the dedicated organ will have more versatility in organ sounds.
So why would I get an instrument that can do electric organ and nothing else when I could get an instrument that can do that and be a host of other instruments as well? There will always be people who want a dedicated organ but the average person is more likely to get a digital piano or similar.
If you’re trying to say that an electric instrument can never be the same as an acoustic instrument, then I agree.
To me the target buyer was a person that wanted to play the church organ. They had to settle for one of these in the home. Remember it was the best synthesizer you had available on the market back then, and the lesser quality from the real instrument was the best anybody could afford. The same household might have a color television or not. You had 9volt transistor radios, and mono cassette recorders, while 8-tracks were components in many audio centers. The music the owners had was normally hymns, show tunes, polkas, and waltzes around here.
I didn’t quite understand this from what you were saying. My electric piano is 7 years old, and though it is a Roland “real electric piano” - not just a keyboard - with about 8 different piano sounds, and a small assortment of others (harpsichord, bass, chimes, etc.), it was the basic model of a full 88-key electric piano, including a reasonable facsimile of key response to speed and pressure of the fingers (“attack”). It’s not a toy, but if it has the capacity to receive added sounds, I don’t know it. It does have a small readable/rewritable memory, (to record, say a single song or score) but that’s it.
Because you’re an organist, or playing organ music? 
For someone who is, or has been, an organist, and who actively uses a pedal clavier when available, there is absolutely no substitute for having three (or more) sets of keys, one of which is underfoot. (Yes, you can split my keyboard between two sounds, and thereby emulate two manuals, sort of, but that’s limited in the combinations you can choose, and amounts to the equivalent of being able to use your right hand and your foot - IOW, treble and bass lines.) 
I don’t feel like I’m producing organ sounds - and certainly not playing as those who know my playing know it, if I’m not using three “manuals” (one with my foot - or feet). And being unable to play with both hands within - or very close to - the same register (i.e., as if both in the treble clef or bass clef) when that’s what I want, is a frustration, to say the least.
I think we’ve had this discussion before. At least there’s somebody that spoke up in a discussion about pianos - acoustic vs. electric - to assert that an electric isn’t, and can’t be, a real substitute for a “real” piano with soundboard. It was at least a year ago, likely two (or more), when (IIRC) a poster asked for advice about buying a keyboard for someone who’d expressed the desire to learn to play the piano. Even with the best possible speakers, etc., there ain’t no substitute for how the harp and soundboard pick up vibrations from all the other strings (and probably there are other factors, but that’s the part I’m sure about). So yes, of course I have a musician’s ear. 
But I guess I’m just more organist than pianist. :sigh:
Rather than receiving added sounds, my Roland has a midi out (which yours probably does too) that allows it to be connected to another piece of hardware or a computer that can have additional sounds added to it.
Yes I realise that. You’d be one of the “people who want a dedicated organ” I mentioned. I think in the past though, a person who wanted a casual musical instrument may have bought an organ where as they would now be more likely to get an electric keyboard. So the popularity amongst casual musicians has probably dwindled.
I don’t know if that was me. My keyboard is obviously not a real piano and it has various shortcomings, however I seem to be getting the same emotional response playing it as I used to playing a piano, so I’m very happy so far (I’ve only had it for a month.)
Keyboards certainly let the person that wanted a piano or such but doesn’t have the space or money something they can play. I wish they had all the keys though. I used to run out of keys on some classical music. I liked what I played, but I didn’t make people listen, because i wasn’t good enough for that. Well except for Halloween I played some horror music with the pipe organ. hooked into the stereo.
Many do. 88 key keyboards and digital pianos are pretty common and can be had relatively cheaply*.
*Compared to an acoustic piano.
Guilty as charged!
I dunno… this guy could probably come up with a way to hook the clock up to the Leslie. 
For years I used a Roland D-50 as a midi controller and got frustrated with not having the full range when I decided to play some piano music.
I got a Casio PX200 for $400 and change. 88 keys, nice feel compared to a lot of other digital pianos I demoed (strictly subjective, of course) and there’s a lot under the hood like a full complement of general midi sounds, USB midi, regular midi, and so on. Downside is that you have to use a bunch of multi-function buttons and a 3 character LED interface to access it all. Comes with a bunch of the classics loaded in and a book of the music. Plus my 5 year old girls like playing the pre-recorded classics and messing with the beats. It’s really quite a treat.
I wouldn’t either. You misquoted and misunderstood me.