The Contributions of Joël Gilbert to the Understanding of "Brassiness"

Joël Gilbert was not only an inspired researcher in acoustics but also an excellent and dedicated trombone player. He combined these twin passions in his work on the science of brass musical instruments and was responsible for several important advances in this field. One of his long-term goals was to identify the factors responsible for musically significant differences between brass instruments with different bore profiles. As a musician he was aware that when played loudly a trumpet or trombone develops a characteristic bright or ‘brassy’ timbre, and in 1996 he was a co-author of the classic paper demonstrating that this ‘brassiness’ results from the generation of shock waves in the trombone. Over the next twenty-six years year Joël collaborated with colleagues in France, the Netherlands, the United Kingdom and the United States in experimental, theoretical and computational studies of the scientific basis and musical applications of brassiness. This paper reviews some of the major steps in the development of a spectral enrichment parameter which can be used to predict the brassiness of an instrument from measurements of its bore profile.