Operator`s manual

272 Version 1.20
APPENDIX G /
In order to make them last longer so that long notes can be sustained, we need to loop them. This
involves selecting a portion of the sound that will repeat over and over again when we hold our
finger(s) on the keyboard.
LOOP ZONE LOOP LOOP LOOP
ORIGINAL SOUND
SUSTAIN PORTION (KEY HELD DOWN)
Note on Note off
The biggest problem, though, is that when you play samples back at anything other than the pitch
they were recorded at, they speed up or slow down - for example, something recorded on C3 but
played back at C4 will play back twice as fast (much like speeding up an analogue tape recorder).
For some sounds this isn’t a problem but instruments with pronounced vibrato or drum or other
musical phrases can suffer quite badly.
Furthermore, most musical instruments have particular resonant frequencies (or ‘formants’ as
they are sometimes called) plus other characteristics such as vibrato, etc.. On the instrument
themselves, these characteristics stay constant regardless of the notes being played but, on a
sampler, because you are transposing the sound up and down, these are also transposed which
leads to a phenomena quaintly referred to as “munchkinisation”. We have all laughed at hearing
our voice speeded up on a tape recorder sounding like some bizarre cartoon character - the same
will happen on a sampler and this is because the voice has string fixed frequency formants and
other attributes which do not transpose well. Similarly, the sound’s envelope will change - transposed
down an octave, a percussive attack will sound quite sluggish.
To overcome this, we need to use a technique known as MULTI-SAMPLING - that is, taking various
samples of the instrument at a variety of pitches across its range so that, at any one time, the
sound is never transposed too much and so avoids serious “munchkinisation” and envelope
distortion. Typically, you can get away with one sample per octave but some difficult instruments
with strong formants need more. The saxophone, voice and piano are two instruments that spring
to mind and which are notoriously difficult to capture. The ideal multi sampling range is to take a
sample every minor third so that the sound is never transposed more than a semitone away from
its original pitch (of course, the ideal multi-sample range is one sample for every note but that’s not
always practical or possible!)
Another property of an acoustic instrument is that it can make so many sounds depending on how
it’s played. When played softly, the sound is not only quieter but softer in tone and, when played
hard, is louder and brighter. Some instruments have quite extreme ranges in tone. Coupled with
playing techniques (i.e. thumbed and slapped bass, bowed and plucked violin, etc.), to accurately
replicate this on a sampler, we can take different samples according to playing styles. On the
S6000 we have four velocity zones that allow us to use playing technique to switch between these
different samples so that you could, for example, use velocity to switch between a slow legato
viola and an aggressively bowed viola.
Of course, a lot of the time you don’t have to go to such lengths and you can simply record just a
few samples, loop them for sustain, map them out across the keyboard and have perfectly acceptable
results which are usable in a wide range of applications (some sounds can even work with just one
sample across the whole keyboard range although this is rare). For some sounds such as drums
and percussion, you don’t even need to loop. However, when you have some multi-samples in
memory, you need to somehow map them out across the keyboard range. This is done in a program.