Each of the 4 operators available in DX21 can be programmed with its own envelope. The envelope applied to a carrier will, generally, contribute to the overall volume envelope of the note, while an envelope applied to a modulator will contribute to the timbre envelope of the note.

Here is a copy of the envelope diagram printed above the LCD on the DX21 panel.

This envelope diagram can be used as a guide in visualizing DX21 envelope settings while you program or edit a voice.

Each envelope generator can be programmed with five different parameters: ATTACK RATE (AR), DECAY 1 RATE (D1R), DECAY 1 LEVEL (D1L), DECAY 2 RATE (D2R), and RELEASE RATE (RR). The RATE parameters determine how fast the envelope moves from one level to the next. The term LEVEL is used rather than “volume” because the envelope of the operator you're working on could affect volume or timbre, depending on whether it is a carrier or a modulator.

Any note begins at zero level when you press a key, then begins to approach maximum EG level at a rate determined by the setting of AR (Attack Rate). The envelope may reach maximum level instantly, or it may take over 30 seconds depending on the setting of AR.

When the envelope reaches maximum level it immediately begins moving towards the next level in the envelope—D1L (Decay 1 Level)—at a speed determined by the setting of D1R (Decay 1 Rate).

The change from maximum EG level to D1R can be either a decrease in level or a sustain at maximum level, depending on the values you choose for D1L.

After reaching D1L, the envelope then begins to decay toward zero level at a speed determined by the setting of the D2R (Decay 2 Rate) parameter. If D2R is set to

0 (no decay), however, the note will be sustained at D1L for as long as you hold the key. Now, when you release the key you have been holding the envelope will immediately begin to decay towards 0 level at a speed determined by RR (Release Rate). In fact, at whatever point in the envelope you release the key the envelope will immediately begin moving toward 0 level at the set Release Rate. Thus ends the note envelope “history”.

THE PITCH EG

In addition to the EG functions just described, the DX21 also has a "PITCH EG". This pitch envelope generator is programmed in a similar way to the individual operator EGs, but it affects the overall pitch of the voice rather than level and timbre. This is useful for creating certain types of voices-whistling, for example, in which the pitch of the note usually starts out a bit low and then sweeps up to the proper pitch.

27