At present, we are faced with two working hypotheses: to refer to an existing universe, stretch its possibilities to the maximum, consciously play with the deformations to be operated on this usual space; or: to seek to renovate musical space, give it flexibility, multiplicity and preserve its coherence at multiple levels.
To begin to discern the possible from the utopian, we need to base ourselves on the perception of musical phenomena and musical objects, studying in particular the perception - both horizontal and vertical - of intervals, and seeing within what limits our auditory perception moves from this point of view.
Going further, we need to study the very idea of limits to perception: limits imprecise by nature, or improvable by habituation or education; also to study the dialectics of these limits when different fields of action or perception are involved.
On the other hand, and musically speaking this time, it is essential to define the nature of the different types of scale that can be used.
- Within the usual definition of the octave
- with a constant unit as a base,
- from non-constant units, varying regularly or irregularly.
- Outside the usual octave definition, by means of an arbitrarily chosen interval.
- With an irregularly defined band, the definition of each band in which the internal interval structure is reproduced can vary according to criteria related or unrelated to these internal intervals.
In relation to these "out-of-text" interval structures, pre-existing any strictly musical structure, we need to study the interference of several essential categories.
- Interference of time: how speed and brevity allow us to perceive interval structures.
- Interference of register: how the enlargement of the first interval by shifting register affects our perception.
- Density interference: the degree to which texture density obliterates interval perception.
- Interference of timbre: to what extent homogeneous timbres or complex, changing timbres help or obscure perception.
- Interference of hierarchy: to what extent scales, an important notion in a universe of simple relations, become secondary when relations become complex in another domain that tends to predominate.
- Process interference: when a pitch grid is modified by another process grid relating to timbre and pitch, to what extent is the original grid still recognizable.