The instance tree implements the timbre specified by the composer. When each Task terminates, the Processor passes it to the Collector, which sums samples from each Note and builds a sound file. The Sound class is the root of a hierarchy of classes, each of which inherits from its parent. This hierarchy is a library of building blocks which can be combined to specify complex timbres. This consistent interface allows objects to pass samples while hiding the algorithms used to generate them.
Sounds are either dependent or independent.
An independent sound can compute samples from its state variables alone. A lookup table oscillator uses only its waveform table, phase pointer, and phase increment to compute its next sample. Dependent Sounds use other Sounds to compute their samples. For instance, a band pass filter has a pointer called source which points to the Sound object being filtered. When Sounds are connected together, they an instance tree.