MODULATE THE FILTER
This project makes those synthesizer like sounds.
It makes the volume of the tones to gradually fade in and out.
At the same time the filter opens and Closes with the fade.
Build the synth like you did in project #03.
connect the wire from the Filter VC to the AMP VC.
Verify that all connections are like the picture.
Finally connect the battery to the power strips.
Mind the color for correct polarity.
The envelope circuit makes a control voltage that changes in time depending on the position of the knob and how long you keep the button pressed.
And the filter now follows the envelope.
This makes those classic synth sweep like sounds.
If you add the diode like you did in project #03 it will sound like a bass synth.