Expansions - many keyboards are designed so that additional features may be purchased and added by the user. These features may include different sounds, arranger capabilities, expanded memory, additional channels, and other things.
Loops - Many parts of music (especially in certain genres - of music styles - example techno) have very repetitive patterns. The synthesist either plays or by other means such as a mouse on computer - the entire pattern, which may be only a couple of measures, or eight measures, or ... Then this sample is set to that it becomes a "loop" - at the end, it starts again.
Patches - also called "programs" by Kurzweil and others. The term originated with the first synthesizers, in which each module of the synthesizer was a self-contained piece of equipment with whatever control knobs, etc. needed for the module's function. Sounds were produced by placing these modules in an order - example: a triangle wave is generated, then passed to a bandpass filter. A separate wave generator called a LFO (low frequency oscillator) is passed to the bandpass filter's filter sweep input. Finally the output signal goes to an amplifier. These modules had sockets for input, output, and any external filetering parameters. The sockets were connected with "patch cords" - simply a cord, like a guitar cord or keyboard cord - that connected them. BTW - there might be hundreds of patch cords for some particular sounds, and hundreds of knobs that were adjusted to manipulate the sound. As time went on - to reduce size and cost, and to make it easier to program; synthesizers (which were a lab device at first, it could take weeks to program a single sound) were built using the most common functions, all in one box, with internal connections between the modules that were most frequently used.
When synthesizers began to be controlled by digital means instead of analog. This meant that the connections and the "knob settings" were all controlled by a digital computer inside the synthesizer. The term "patches" is just a carryover to this day. You might have a "patch" named WhiteSatinSplit (an actual program from a Kurzweil PC2 with the Vintage Keys module added) this is a synthesized group of three sounds made to approximate the sounds of Mellotrons as used in the Moody Blues' song "Nights of White Satin."
Current synths generally have hundreds of "factory patches." These are the generic sounds programmed in by the factory sound designers. Many of them are designed to sound like some famous sound of the past, although names are disguised a bit to avoid trademark and copyright problems. It takes a very considerable amount of time and work to learn how to program these sounds, and much of the knowledge does not translate well to another manufacturer's designs (or even between different models of some manufacturers.)
Most of the world class performers either have learned to make custom "patches" so that they have their own distinctive sounds - so their Yamaha Motif model ABC won't sound like your Yamaha Motif model ABC; or they have hired people specifically to come up with customized patches. This is one major reason that the big three synth companies can come out with a new model every couple of years - that is the same basic old synth with a new set of programs - where the factory designers "copy" the sounds from the past couple of years hits.
So - if you really want your MO8 to sound just like (insert performer's name)'s Motif - you have a pretty steep learning curve and lots of time copying their sounds. Or - you could just do as the leaders do - and spend that time developing your very own personal sounds (or you can just lay back and play the keyboard's internal sounds and spend your time getting the very best personal results that you are able from the stock sounds).
One of the reasons that I own a number of Kurzweils is that I have found a larger percentage of "out of the box" good useful sounds. It is not helpful at all to have 900+ factory sounds - and only 14 or them are useful to me.
Jim
