Yamaha DX7 II FD Reference Manual page 28

Portamento
Portamento is a voice effect found on even the earliest synthesizers. It allows you to
"glide" smoothly from one note to another. For example, a piano cannot be played with
portamento. A violin, trombone, or even a human voice can glide from note to note very
easily. The DX7 II provides very flexible portamento parameters which are described
below.
Mode
Portamento mode determines the type of gliding between notes in conjunction with the
key mode. The following parameters are available when a polyphonic key mode has been
selected.
sus-
key
p
retain
(sustain: key pitch retain) Portamento will not affect notes
being sustained by a hold pedal. Pitch of sustained notes is
retained.
sus-
key
p
f
o 11 ow (sustain: key pitch follow) Portamento will affect the pitch
of sustained notes. The pitch of the sustained sound glides to
the pitch of the next key(s) played, "following" those keys.
In either of the mono key modes, the following portamento modes are available.
f i n
g
e red
Glide will occur only if a second key is pressed before the first key is
released. This gives you finger-tip control over the portamento effect.
A slightly "portato" playing style (releasing a key very briefly before
playing the second key) avoids portamento. An exaggerated legato
playing style (releasing a key an instant after playing the next one) will
provide portamento between notes.
f
u 11
t i me
Portamento is applied to all notes at all times. Pitch gliding is applied
even when playing staccato.
The best way to understand these two sets of modes
is
to
try
them out. Be sure that the
time parameter (see below) is set to 70 or so in order to hear the effects.
Step Like the pitch bend step function, the portamento step parameter allows pitch gliding to
occur in "steps" or jumps. These steps are selected by the following values.
0 Portamento occurs smoothly with no steps.
1
Portamento occurs in steps of 1 semitone.
12 Portamento occurs in steps of 12 semitones (steps of 1 octave).
This parameter is used to create the effect of rapidly played scales. A step value of 1
causes chromatic scales to be played between notes.
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