Another handy module we may want to create is a “Delayed LFO”. This is an LFO where the output level starts out at zero, and the LFO output gradually increases over a period of time. Again this is quite easy to replicate with a few more modules added into the LFO structure.
Delayed LFO with linear fade in.
Here I have used the TD_LFO_B. Essentially all we need to do for the slow fade in of the LFO level is to use an ADSR module triggered from the Keyboard. The Attack portion of the envelope, and the overall output level are the only ADSR parameters we need to control, so for the others a Fixed Values (Volts) module can be used with the following voltages set; Decay = 0V, Sustain = 10V, and finally Release = 4V the latter being to give a fade out rather than an abrupt end to the LFO output.
As the LFO doesn’t need to be Polyphonic we put the two voice combiners into the Trigger and Gate lines to force the modules into Mono mode.
Note: For the ADSR2 to work correctly both Trigger and Gate plugs must be connected to the MIDI interface module in use. This structure however, only gives us a linear fade-in.
Delayed LFO with a non-linear fade in.
In the structure below we have changed the ADSR module to give us a range of different fade-in curves, it’s now the Community ADSR (Download from https://www.synthedit.com/modules/), which allows you to specify the curve of the envelope by changing the voltage on the Attack Curve, Decay Curve, or Release curve. In our case we only want to change the Attack Curve. The range for this plug is from -5 Volts to +5 Volts which gives us a variation from an exponential curve (-5V), through linear (0V) to a logarithmic curve
Logarithmic curve.
Exponential curve
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