Channel

All of Boodler's sound-generating elements exist in a tree of channels. This is a hierarchical tree; operations on a channel (stopping it, changing volume, etc) affect all the channels underneath it. If you do something to the root channel, it affects everything.

Agents can create new channels whenever they want.

A channel lasts for as long as it's in use. A channel ends when it has no sounds, agents, or channels beneath it.