Vocal & Choir sounds

To simulate singing voices, you first need to take a (grossly oversimplified) look at the human sound reproduction stages.

We have:

• some envelopes + control signals (the brain)
• noise (air from the lungs)
• an oscillator (vocal chords)
• a few resonators/filters (all the cavities)
• an output (mouth)

The filters will need to be tuned to frequencies that our brain recognizes as official formants:

copied from: formant frequencies on wikipedia