This bit breaks down the three global output parameters in Ableton's Bouncy Notes device, which turns a physics-based ball simulation into MIDI notes. Velocity Ball sets how much the speed of a ball's impact on the piano roll shapes the outgoing note velocity, so turning it down flattens every hit to the same output level regardless of how hard the ball strikes.
Thru works like a dry control, but for velocity rather than signal. It governs whether notes played directly from your MIDI keyboard pass through the device at all, turned all the way down and your live playing goes silent.
Gain acts as the wet counterpart, scaling the velocity of notes generated by the bouncing balls themselves. Raising it pushes those ball-triggered notes louder, giving a simple way to balance your own playing against the device's generated pattern.