Abstract:

The purpose of this research is to establish perceptually relevant operational definitions of the acoustical segments of isolated musical instrument tones. Previous research has yielded conflicting conclusions for continuant (nonpercussive) tones regarding the relative salience of the attack and steady-state portions. This study also examines the perception of impulse (percussive) instrument tones. A new model for the partitioning of continuant tones, the ``amplitude/centroid trajectory,'' divides the signal into four segments: The attack, attack/steady-state transition, steady state, and decay. The divisions are based on the direction of and relationship among the global rms amplitude and spectral centroid. Other operational definitions of signal partitions and reverse playback were included as editing treatments. Single isolated tones were used from six impulse and six continuant instruments. Nine subjects participated in a 246-item forced-choice identification experiment. It was determined that, for sustained continuant tones, the steady state alone provides sufficient and necessary information for the identification of the instrument. The coevolution of the amplitude and spectral centroid seem important, but the direction does not. A confounding of envelope with identification for staccato tones was found. For impulse tones, both the direction and coevolution of global components are necessary.