FluidR3 GM Choir Aahs. Fluid Soundfont by Frank Wen and contributors. MP3 rendering by gleitz/midi-js-soundfonts. CC BY 3.0.
https://github.com/gleitz/midi-js-soundfonts
https://creativecommons.org/licenses/by/3.0/
Samples unmodified; runtime gain, envelope and pitch adjustment.