MusicModel

The MusicModel module defines a database for storing musical information.

Model

The Model object is an aggregate of information describing the performing forces (Performer, Instrument, and Voice), and the musical information which is actuated by them.

Model.Fragment

A Model.Fragment is the product of slicing up a Model with a Model.Filter. A Model.Fragment is a representation of a Model in a particular interval of musical time, performed by a constrained set of performing forces, within a set of desired types of musical information (e.g., Pitch, Dynamics, etc.).

Model.Filter

A Model.Filter is a composition of three axes of constraint used to create a Model.Fragment: an interval of musical time, a set of performing forces, and a set of the types of musical information to retain.

PerformanceContext

The PerformanceContext of a Model is an aggregation of Performer, Instrument, and Voice structures. In a PerformanceContext, there are any number of performers and instruments. A performer can play one or more instruments, and a single instrument can be played by one or more performers.

A Performer-Instrument pair can manifest in one or more voices.

Examples

Solo

The most basic example of a PerformanceContext is one in which there is a single Performer, playing through a single Instrument, with only a single Voice.

Simple Solo

For example, imagine a single flutist performing monophonic material.

Complex Solo

Often, music for a single instrument can be polyphonic, where multiple voices are performed concurrently by a performer. This can be modeled with a single Performer playing through a single Instrument, with multiple Voice values.

In the case of a percussion solo, for example, there is often more than one instrument played by a single Performer.

Complex Solo

In this example, a single percussionist could be playing three different instruments (e.g., snare drum, bass drum, triangle). In this case, bass drum and triangle are polyphonic. That is, there may be concurrent figures on the same instrument which are notated with different rhythmic values.

Each Performer-Instrument pair has one or more voices, each being unique to it.

Ensemble

Very often, people play music together. A relatively straightforward example of this is a string quartet, in which each performer’s material is monophonic.

Simple Ensemble

Intertwined Ensemble

There are often cases in which multiple performers play on the same physical instrument. This happens commonly in percussion ensembles.

Intertwined Ensemble

In this case, imagine four percussionists, playing on two different physical instruments. Each Performer-Instrument pair emits a single, unique voice.

PerformanceContext.Filter

A PerformanceContext.Filter is used to focus in on a subset of a PerformanceContext. It can be specified by indicating specific Performer, Instrument, or Voice values which are to be retained.

A PerformanceContext.Filter can be initialized with sets of Performer, Instrument, and/or Voice values.

let filter = PerformanceContext.Filter(
    performers: [performerD], 
    instruments: [], 
    voices: [voiceB]
)

The default value for each parameter is an empty Set. If an empty set is given for a parameter, the filter will not use that parameter for constraining the PerformanceContext. Thus, if no parameters are given (.init()), no constraints are enforced by the filter, and the original PerformanceContext is returned in its entirety.

Filtering by `Performer`

When filtering a PerformanceContext with a set of Performer values, all of the voices emitted by all of the Performer-Instrument pairs including the given Performer values are retained.