In TouchDesigner any CHOP channel can drive any operator parameter, so audio, MIDI and beat inputs are interchangeable

TouchDesigner’s CHOPs (Channel Operators) carry time-varying numeric channels, including live audio. Once you have a numeric channel you can wire it into the parameter of any other operator (a geometry’s scale, a colour, a blur radius), which turns ‘audio reactivity’ into a wiring-and-mapping problem rather than a scripting one: connect a channel to a destination and remap its value range. The key insight this tutorial stresses is that the input modality is abstracted — the driving channel does not have to be extracted audio. MIDI, TDAbleton (Ableton Live link), and a Beat CHOP work equally well, so you can swap the source of a reactive network without rewriting what it drives. The same CHOP chain that pulses to a kick can be repointed to MIDI velocity or a tempo-locked beat.

Examples

Feed an audio amplitude channel into a shape’s scale parameter so it pulses with the music, then replace the audio source with a Beat CHOP or MIDI channel — only the source wire changes, the rest of the network stays the same.

Assessment

Explain why, in TouchDesigner, an audio-reactive network can be converted to a MIDI-reactive one by swapping a single input, and identify what stays constant in the network.