Passive LPG is live!!
Here, the VCO is sending a pure square wave melodies into the low pass gate. The Maths is in repeat mode, sending very short envelopes to the LPG.
In the middle, the switch lets all the sound through and accents the sound with the control voltage coming in.
But switched to the top (bouncy!) and bottom (mellow!), the filter slope is modified by bigger capacitors so that only the CV pings can be heard.