Hierachical live-looping is a musical technique for live performance. It aims at combining the immediacy and expressiveness of the live-looping technique with new possibilities for the creation and manipulation of musical structures.
The main idea is to define live-looping trees. Leaves of these trees are simple sound synthesis processes, with common parameters such as pitch, volume, noisiness, and resonance. Higher level nodes are either "loop nodes", i.e. they contain looped recorded events sent to their children, or "sync nodes" which can synchronize several loop nodes in many ways.
Nodes of each level can be modified separately and parameters modification of parent nodes are passed on to the children, so that one can set the overall volume of a recorded loop. Various operations can be applied to trees. One may record loops to create loop node, merge loop nodes to create a sync node, duplicate a tree or parts of it, or echange nodes in a tree.
Hierarchical live-looping is implemented in the Drile immersive virtual musical instrument.