This paper presents a model for the harmonic description of musical signals
using schema-based chord decomposition. The model is based (i) on a bottom
-up processing of musical signals into auditory images of different kinds a
nd (ii) on a schema-based top-down processing of the images which produces
chord decomposition. The schema is carried by a neural network and its cont
ent is derived from the self-organization of a pre-selected set of chords i
n all keys. The system architecture of this model is described and its perf
ormance is analyzed in detail through several excerpts of piano pieces. An
evaluation procedure has been developed to compare the results with the one
s derived using a music theoretical approach to chord decomposition.