I was helping out a person who saw the project at the Maker Faire and wanted his own adaptation of this controller; he would like to have 88 keys in piano style, but he also wanted standalone audio support; as you may know, my project currently support either Standalone Audio and 48 analog controls, or 144 controls and no audio. Besides RAM usage and polyphony issues that could arise, with the current configuration he won't be able to achieve his goal, I initially thought.
But then, BANG! I thought that rather than using single pins for each INHIBIT of the 3 HCF4067 that can be plugged on the mobo, I could use those 3 pins as the 3-bits control bus of an 8 channel mux with its common input set to 5 V and its outputs set as INHIBITs of up to 8 HCF4067 which will still share their 4-bits control bus as well as one single analog pin.
If we could also reach in a reasonable way the pins on the backside of the Teensy, we could use the same architecture to control way more analog inputs!
Stay tuned for another revision of this project!