In this phase of this research, the acoustical signals generated in expressive performance by orchestral instruments are parsed. Most studies of musical expression and performance have concentrated on the profiles that arise from MIDI timing data. Here, the signals of ordinary orchestral instruments are employed from these studies of expressive communication, and analyses are provided that map timing, amplitude, and spectral measures to performer messages. Different instruments have different combinations of drivers, resonators, and couplings, and the resultant acoustical signal contains information about these. Recently, in the laboratory, Hajda has explored spectral centroid trajectories as a means of identifying attack characteristics, and this notion is applied to the issue of legato transitions in expressive musical performance. Timing and amplitude trajectory data from these experiments suggest that, while lesser musicians have a tendency to repeat similar gestures over the range of expression, highly trained performers at a virtuoso level are capable of distinct timing profiles under stylistically appropriate conditions which communicate their intent.