There is far more to "rompler" style synthesis than simply playing back
a sample. The difference between sample-based synthesizers and those
pieces of gear we specifically call samplers is pretty easy to spot.
The chief role of a sampler is to capture and reproduce a sound. This
is a dynamic process that usually takes place over a single production,
or even during a single performance. Usually only endpoints and pitch
are adjusted, and a simple filter and effect are applied to the sample
to fit it into the mix. The vast majority of sample collections are
designed for this style of synthesis.
Sample playback synthesis, on the other hand, starts in a tightly
controlled recording studio with a quality instrument, a skilled
performer, and a painstaking and tedious process to try to get multiple
samples to sound like one instrument. Once you end up with a good set
of samples of an instrument, you have a fine musical tool, but it's
still got a long way to go before it's musically useful as part of an
ensemble. A sample is just a recording of a single event. It has no
more expressive flexibility than CD recording of a performance.
maps have to be applied, controllers have to be designed, and if the
instrment was multisampled, elaborate crossfades have to be built. This
takes even longer than recording, and the end result is something that
usually will work on only one instrument; each manufacturer has a
different sound synthesis architecture, so a complete performance for a
Yamaha is completely incompatible with a Roland. Most manufacturers now
provide expansion boards with samples and control data stored together.
Romplers are designed so that the user doesn't have to worry about the
samples he or she is using.
What I'm getting at is that a good sample is only a starting point for
a musician that wants good orchestral sounds. A good synthesizer, in
the Moog/Arp/Nord sense, generates a rich, textured sound that is full
of life and allows a performer to express, not simply play, a part. The
same is true of a sample-playback synth. You don't want the same exact
noise every single time you hit the same note.
I'm partial to Roland's XV/SRX sounds. Some of Yamaha's sounds are
nicer when you solo them IMO, but I've found that the Rolands blend
better in a mix while Yamaha's tend to step on each other without