Recorded instrument samples from tonejs-instruments, curated/edited by Nicholas Brosowsky. CC BY 3.0: https://creativecommons.org/licenses/by/3.0/
https://github.com/nbrosowsky/tonejs-instruments
Original sources: Iowa (acoustic guitar), Karoryfer (bass), VSCO Community (violin, contrabass), flcellogrl on Freesound (cello). See NB-sample-source-info.txt.
Viola and banjo: FluidR3_GM, MIDI.js Soundfonts by gleitz. CC BY 3.0 US: https://creativecommons.org/licenses/by/3.0/us/
https://github.com/gleitz/midi-js-soundfonts
Fluid soundfont author: Frank Wen and contributors.
Changes: selected MP3 notes; FluidR3 note payloads extracted without re-encoding. Runtime playback transposes recordings to selected tuning frequency, applies gain and a short end fade. Guitar recordings are also used as explicitly labelled reference tones for ukulele, mandolin and balalaika.