Computer Study of Trumpet Tones

A study of the trumpet tone quality has been undertaken to determine the important physical correlates of trumpet timbre. Musical fragments played by a professional trumpet player have been recorded; selected tones have been converted into digital form by sampling at 10‐kcps rate for subsequent spectral analysis. The computer analysis has yielded displays of the amplitude of each harmonic as a function of time (one point per fundamental pitch period). From these displays and computer sound‐generation programs, tones were synthetized that proved to be indistinguishable from the real tones by skilled musicians. By systematically altering the tones' parameters, it was found that a few physical features were of utmost aural importance: the attack time (which is shorter for the low‐frequency harmonics than for the high‐frequency ones), the fluctuation of the pitch frequency (which is of small amplitude, fast, and quasirandom), the harmonic content (which becomes richer in high‐frequency harmonic when the loudness increases). From only these features, it was possible to synthetize brasslike sounds.