Yamaha Electone EL-87 Owner's Manual page 94

N O T E :
The parameter value can be changed
quickly when you press the Data Control
button with the COARSE button held.
90
(2) To edit the FM Operators:
1
Adjust the Envelope Parameters of Operator 1 (after turning off
the other Operators).
The Envelope Parameters control the level of the sound and
how that level changes over time. See page 99 for more
information.
For now, try making some of these changes in the envelope:
Adjust the OL (Output Level) parameter.
Changing the OL parameter affects the volume of the selected
Operator.
Raise the OL parameter from 0 to 110 by using the pair of Data
Control buttons just below the OL. (Pressing the [Å¢] button
raises the level, and pressing the [ŧ] button lowers the level.)
Adjust the AR (Attack Rate) parameter.
Play the voice and notice how the changes you make affect the
initial volume of the voice. By changing this parameter you
can make the sound gradually get louder (lower settings) or
have it reach its full volume all at once (higher settings).