Motomouth is an analogue 3-Band, Sedra + Espinoza Bandpass Filter (DABP) with resonant frequencies that are tuned to the same resonant frequencies found in the human mouth and nose cavities, and these can be varied, independently, to form different ‘mouth shapes,’ to emulate vowels such as A, E, I, O and U. Motomouth can emulate 16 vowels and ‘morph’ or ‘glide’ between each vowel using a single Control Voltage input (1V/Oct), and a Gate to ‘snap’ to each vowel when required.
Two of the bands (F1 and F2) are used to form the mouth cavity, and the third band (F3) is used to from the nasal cavity, which is reasonably static. Varying F3 makes little significant difference ‘in the mix,’ but having it is important.
The single Control Voltage is decoded to control F1 and F2 independently, because the frequency bands for each vowel are not proportional to each other over the vowel range. So Motomouth has learned how to ‘speak,’ so to speak, but it still needs to learn more, and that’s where you come in.