Ligeti's music is based on several aspects.
Some of them are strictly connected to the music as heard.
Works like "Continuum", "Chamber Concert", "Atmosphères", and many others are based on aural illusions.
The ordinary ways of analysis are insufficient a nd inadequate to interpret
the complexity of this phenomena.
Aural Sonology Project (ASP), created and managed by the Norwegian composer and researcher Lasse Thoresen is a very exhaustive answer to this analysis problem.
Integrating the methodology of ASP with an appropriate study of sound spectra, harmonics, interactions of heterogeneous temperaments, microtonal system, quarter tones, harmonic series of non-harmonic pitches, acoustic interconnection in multi-layers and polymetric structures, it is possib le to obtain a complex and exhaustive overview of the relationships between the Ligeti's techniques of composition and the acoustic results achieved by the knowledge of aural perception.
Music is not what it is fixed on paper, it is what is perceived by e ar.
The notes are just a way to preserved what the imagination has created.
ASP is an attempt to analyze music as represented on a phonogram, rather than on a score.
The musical object is not entirely an objective fact but is partly constituted by the lis tener's intentions.
A deep study of semiotic and notation will be carried out, believing the analysis about the symbols can explain the relation between the signs and graphismes on one hand and the sound that can be heard on the other one.
In this sense a n investigation on the Pictographic writing can offer interesting results.
In the end a significant research on electronic music, notated by a not-conventional system (usually aural scores and graphic notation replace the ordinary symbology), will clarify how the musical structures, even in the not-acoustic world, are not involved into inexpressive intellectual mechanisms but they belong to the process of imagination that is deeply connected to aural perception.