Even identical notes vary measurably across every repeat performance

Evidence

By way of a caveat it should be noted that these figures are presented to provide only examples of the general nature of the acoustics of the note onset phases for these instruments. Had these notes been played at a different loudness, by a different player, on a different instrument, in a different environment, or even just a second time by the same player on the same instrument in the same place while attempting to keep all details con­ stant, the waveforms and spectra would probably be noticeably different. — David Howard, Jamie Angus, coustics and Psychoacoustics, 1473 (#expands, via linked claim)

The timbre of a principal organ stop sounds “steady” during a prolonged note such as that plotted, which lasts for approximately 2 seconds, but it is clear from the acoustic pressure waveform plot in Figure 5.1 that the ampli­ tude, or “envelope,” varies even during the so-called “steady-state” portion of this note. This is an important aspect of musical notes to be aware of when, for example, synthesizing notes of musical instruments; particularly if using looping techniques on a sampling synthesizer. — David Howard, Jamie Angus, coustics and Psychoacoustics, 1464 (#expands, via linked claim)

Categorization

• XREF: connects to: Even identical instruments playing in unison produce uncorrelated waveforms.; Instrument note onsets vary hugely across takes, players, and environments — David Howard, Jamie Angus, coustics and Psychoacoustics, 1473; A steady-sounding note still has amplitude envelope variation within it — David Howard, Jamie Angus, coustics and Psychoacoustics, 1464 (+1 more)

Broader Connections

• Instrument note onsets vary hugely across takes, players, and environments #expands (0.90) — David Howard, Jamie Angus, coustics and Psychoacoustics, 1473
• A steady-sounding note still has amplitude envelope variation within it #expands (0.75) — David Howard, Jamie Angus, coustics and Psychoacoustics, 1464