Modular has one secret: audio and control voltage use the same cables. That one idea unlocks every patch, trick, and technique in the format.
Modular has one secret: audio and control voltage look the same to the rack. Same cables, same jacks, same voltages. Only the speed differs.
On the scope you see two signals. The VCO on CH1 is zipping back and forth hundreds of times per second - that is audio. The LFO on CH2 is lumbering along at 1 cycle per second - that is CV, control voltage.
Audio goes into your ears. CV goes into other modules to turn their knobs for you. The same cable can carry either one. This one idea is the foundation of everything else in this course.