1 - Roland

Chapter 3. Creating Your Own Sounds
Note on Tone Editing
Because the XP-30 is designed to create wholly realistic
sounds, editing necessarily affects the complex PCM
waveforms sound are based on. So if you try to create a
sound which is totally different from the original waveform,
the results may not be what you want. XP-30 waveforms are
divided into:
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 XP-30’s
one-shot waveforms are sounds that are
complete in themselves, such as percussive
instrument sounds. The XP-30, however,
contains many other one-shot waveforms that
are only partial elements of sounds. These
include attack components such as piano
hammer sounds and guitar fret noises.
Looped: These waveforms contain sounds with long
decays or sustained sounds. With looped
waveforms, the latter part of the sound is
generated repeatedly over a specified portion of
the waveform for as long as the note is held
(allowing wave memory to be used more
efficiently). The XP-30’s looped waveforms
include such sound components as piano string
vibrations and hollow sounds of brass
instruments.
The following diagram shows an example of sound (electric
organ) that combines one-shot and looped waveforms.
fig.3-09.e
TVA ENV for looped Organ
waveform (sustain portion)
Key-off
TVA ENV for one-shot Keyclick
waveform (attack portion)
+ =
Resulting TVA ENV change
Key-off
Notes for Editing One-Shot Waveforms
An envelope cannot be used for giving a one-shot waveform
a longer decay than the original waveform’s, or make it a
sustaining sound. Even if you were to make such envelope
settings, you would simply be controlling a non-existent
portion of the sound, so such settings would have no
meaning.
Notes for Editing Looped Waveforms
With many acoustic instruments like piano and sax, radical
timbral changes occur during the first few moments of the
note. This initial attack is what defines much of the
instrument’s character. The XP-30 provides a variety of
waveforms containing realistic acoustic instrument attacks.
To obtain the maximum realism when using these
waveforms, it is best to leave the filter wide open during the
attack. This way, all the complex timbral changes can be
heard. For the decay portion of the sound, you can use the
envelope to produce the desired changes. If you use the
envelope to modify the attack portion as well, the natural
attack contained in the waveform itself will not be heard to
full advantage, and you may not achieve the result you want.
fig.3-10.e
Tone change stored
with the wave
Envelope
for the TVF filter
Resulting tone change
Looped Portion
If you try to make just the attack brighter and subdue just the
decay using the TVF filter, you need to keep in mind the
timbral characters of the original waveform. And particularly
if you’re making a part of the sound brighter than the
original waveform, you should first generate upper
harmonics (not present in the original waveform) using
Color and Depth parameters (PATCH/WAVE/FXM) before
filtering. If you don’t, the results will be disappointing. To
make the entire sound brighter than the original waveform,
try adjusting effects such as enhancer and equalizer before
modifying the TVF parameter (PATCH/TVF).
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