Roland XP-30 owner manual Creating Your Own Sounds

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.

TVA ENV for looped Organ	TVA ENV for one-shot Key-
waveform (sustain portion)	click waveform (attack portion) Resulting TVA ENV change

+	=
Key-off	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.

Looped Portion

Tone change stored with the wave

Envelope for the TVF filter

Resulting tone change

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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