What is it?
With the Low Pass Filter Envelope you can attenuate (lesson) the high frequencies of a sound with control over time, and with the LFO you can modulate the amount of filtering with control of the depth over time.

How to use it
The Low Pass Filter Envelope has the following two parameters, Range and LFO.  The default parameters will not do any filtering (after Reset).

The Range popup menu can have a value of x4 to ÷12, it controls the maximum amount of filtering the envelope can have when it is processed.  A Range of x1 to ÷12 uses a -6 db per octave filter, x2 is -12 db per octave, x3 is -18 db per octave, x4 is -24 db per octave.

The LFO dialog box lets you modulate the filter.  When a waveform is selected, the envelope controls the depth of the LFO.

Notes
See "Envelope", "LFO", "Reset", and "Glossary" for more information.