From: Rich Eakin <rtepub@gmail.com>
...
Is anyone aware of studies, articles, or other research that has been
conducted around the amplitude envelopes of real world music instruments
(strings, brass, voice, etc) during performance? What I mean is, I've seen
a few articles here and there that explain how the envelopes differ between
musical instruments (such as figure 5 of this article
<http://interscience.in/IJCSI_Vol2Iss1/IJCSI_Paper_4.pdf>), but the source
analysis samples are too simple for musical usefulness, usually a single
note recorded with basic dynamics. What I'd like to find is more how the
ADSR curves look for actual musical phrases.
...
cheers,
Rich

Welsh's Synthesizer Cookbook is a great resource. The author "reverse engineered" common instrumental sounds to make recipes for dual oscillator synths with waveforms, noise, modulation, filters and ADSR envelopes for both the amplitude and the filter. The CDROM with the book includes a VSTi synth to recreate the recipes. Volume 2 has harmonic spectrum of the instruments similar to the diagrams in Fig 2 of the paper you reference.

The CCRMA site https://ccrma.stanford.edu/software/snd/snd/sndscm.html is an awesome reference, anders, thanks for sharing,

-- Jeff