The usage of the computer gave way to two types of approaches, the first the manipulation and the modelisation of sound and music data, the other making use of the multimodal possibilities. Computational analysis naturally turned to the symbolic paradigm that, applied to music, consists in analysing the symbols of the score (notes, chords, durations, rhythms, dynamics, etc.). We present a novel approach to analysis assisted by computer based on the sub-symbolic paradigm. Retrieving sub-symbolic data from psychoacoustics descriptors offers the possibility to approach the perception of several musical dimensions such as time (tempo, attacks, durations), pitch (roughness, salience, multiplicity, tonal clarity, etc.) and timbre (brightness, inharmonicity, profile, spectral clarity, etc. These tools are particularly adapted to 20th-century music and afford original solutions for the analysis of large-scale processes. In order to illustrate the usage of psychoacoustic descriptors, some of them are put to use for the analysis of Luciano Berio's Sequenza VII. They give answers to precise questions concerning the repartition of attacks in function of the piece's temporal canvas, on the perceptive salience of pitch classes and on tension/relaxation phenomena produced by the combination of sensory and harmonic dissonances.