Yamaha DX7 II FD Reference Manual page 15

When a note is played, its pitch level starts at IA from the last note played. The pitch level
moves
to
L1 at rate Rl, then to L2 at rate R2, and then
to
L3 at rate R3. The pitch stays at
L3 until the key is released at which time it moves to IA at rate R4. Unlike the operator
EGs, IA is not necessarily set to 0.
Pitch envelopes can be very effective for a number of voices such as electric bass or
plucked strings. However, it can become difficult to stay in tune with other instruments
when you have set IA to a value other than 50. To avoid this, set the pitch EG rate R4 to 0
or shorten the voice's release time by increasing the R4 rate in the carrier envelope(s).
Rng
The Rng (range) parameter determines the difference between the pitch level values 0
and 99.
1
I
2oct Maximum pitch difference is 6 semitones
(Vz
octave).
loct Maximum pitch difference is 1 octave.
2oct Maximum pitch difference is 2 octaves.
Boct Maximum pitch difference is 8 octaves.
Special effect voices often use large pitch range values
to
produce some rather crazy
sounds.
Vel The Vel (velocity) parameter allows you
to
control the intensity of the pitch EG's effect
with key velocity. As the keys are played harder (faster), the changes in pitch specified by
the pitch EG become larger.
off Key velocity has no effect on pitch EG.
on Key velocity effects pitch EG.
This parameter gives you very realistic control over "natural" voices such as bass, and can
add a great deal of expression to "synth" voices.
Rs
This parameter performs the same function as the operator EG rate scaling. In this case, it
affects the pitch EG. It determines the extent to which the pitch EG rates will speed up as
higher notes are played on the keyboard.
0 Pitch EG rates will not be affected by playing higher keys.
7 Pitch EG rates will be most strongly affected by playing higher keys.
As you play higher notes on the keyboard, the pitch EG rates become faster. Like operator
EG rate scaling, this aids in creating more natural sounding voices.
- 12-