Cautions When Selecting A Waveform - Roland Fantom XR Owner's Manual

Creating a Patch
If you don't need a tone, save the patch with that tone switched
off. This will conserve polyphony.

Cautions When Selecting a Waveform

The sounds of the Fantom-XR are based on complex PCM
waveforms, and if you attempt to make settings that are contrary to
the type of the original waveform, the results will not be as you
expect.
The internal waveforms of the Fantom-XR fall into the following two
groups.
One-shot: These waveforms contain sounds that have short decays.
A one-shot waveform records the initial rise and fall of
the sound. Some of the Fantom-XR's one-shot
waveforms are sounds that are complete in themselves,
such as percussive instrument sounds. The Fantom-XR
also contains many other one-shot waveforms that are
elements of other sounds. These include attack
components such as piano-hammer sounds and guitar
fret noises.
Looped: These waveforms include sounds with long decays as
well as sustained sounds. Loop waveforms repeatedly
play back (loop) the portion of the waveform after the
sound has reached a relatively steady state. The Fantom-
XR's looped waveforms also include components of
other sounds, such as piano-string resonant vibrations
and the hollow sounds of brass instruments.
The following diagram shows an example of sound (electric organ)
that combines one-shot and looped waveforms.
fig.06-005.e
TVA ENV for looped Organ TVA ENV for one-shot Key
waveform (sustain portion) -click waveform (attack portion)
Level
+
Time
Note off
Cautions When Using a One-shot
Waveform
It is not possible to use the envelope to modify a one-shot waveform
to create a decay that is longer than the original waveform, or to turn
it into a sustaining sound. If you were to program such an envelope,
you would be attempting to shape a portion of the sound that simply
doesn't exist, and the envelope would have no effect.
48
Resulting TVA ENV
change
=
Note off
Cautions When Using a Loop
Waveform
With many acoustic instruments such as piano and sax, extreme
timbral changes occur during the first few moments of each note.
This initial attack is what defines much of the instrument's character.
For such waveforms, it is best to use the complex tonal changes of
the attack portion of the waveform just as they are, and to use the
envelope only to modify the decay portion. If you attempt to use the
envelope to modify the attack portion as well, the characteristics of
the original waveform may prevent you from getting the sound that
you intend.
fig.06-006.e
Level
Tone change stored
with the wave
Envelope
for the TVF filter
Resulting
tone change
Looped portion
Time