Chapter 6 - Advanced Applications
Local Generators
The Q20 is equipped with two Local Generators which can be used as Modulation Sources. Each Local Generator can be set to either one of five types: Input Envelope, Peak Follower, Ramp, LFO or Footswitch. The first three allow different ways of having the audio signal at the Q20Õs inputs modulate the parameters of a Program, and the second two use internal sources. The Input Envelope, Peak Follower and Ramp Local Generators may be triggered by either the Left Input or Right Input, or both Left and Right Inputs. They may also be triggered by the Digital Input, if Optical or S/PDIF Data is selected as the Input Audio Source (on Global Page 4).
Input Envelope. This uses an envelope, similar to the type found in most synthesizers, which is triggered once the audio signal at the Q20Õs input(s) exceeds the Attack Threshold you have chosen
ON THRESHOLD
AUDIO PEAK INPUT
(Left or right Channel or higher of left and right)
OFF THRESHOLD
MAX MODULATION
ENVELOPE OUTPUT 
0
ATTACK TIME | DECAY TIME |
Peak Follower. The peak follower will follow the audio input to its loudest point and, as the input level drops, the peak follower drops at a constant rate determined by the Decay time (0.20Ð10.00 seconds). Once the input level exceeds the Peak FollowerÕs level, the Peak Follower is raised to accommodate the higher level, and then (as the input signal again falls) proceeds to fall again using the same Decay time. Since the input levels may be too low at times for the Peak Follower to have ample effect, its Gain may be set to multiply the inputÕs level from x1 to x99.
Peak Follower 1 and 2 have identical features and work as shown below:
SLOPE IS SET BY DECAY TIME
PEAK FOLLOWER OUTPUT
AUDIO PEAK INPUT | (Left or right Channel or |
| higher of left and right) |
96 | Q20 Reference Manual |