Originally written in a facebook post: “How to build a basic midi-playable synth?”
You can check the patch in the Download section.

“The audio is being generated in the VCO, then goes to a VCF, then to a VCA and finally reaches the final output.

You will need the synth to track the pitch of the keyboard, so connect the 1V/OCT output in the midi module to the V/OCT input in the oscillator.

Then, you will need the envelopes to fire when a key is pressed. So, you can do that by connecting the gate output of the midi module to both ADSR envelopes.

To control the amp with an envelope, connect its output to the Exp or Lin input in the VCA. Then, to control the cutoff frequency with the other envelope, connect its output to the Freq input in the VCF, and turn the Freq CV knob.

You can then expand on this basic synth however you like. For example, I’ve replicated the structure of a minimoog-style synth:
The differences with the first version are:
1.- Three oscillators instead of one. The pitch is going to all of them, so they play the same note. Also, i added a mixer to fuse them together before going to the filter
2.- The modwheel is now controlling the vibrato amount. To do this, i’m using the A*B+C module: C is the pitch going out the midi module. This is added to the multiplication of a LFO and the modwheel, so if the modwheel is at 0, the pitch remains the same, but if the modwheel goes up, the LFO starts to act on the pitch.”