in the 3rd "episode" I'll talk about the resonator block. There's so much to say, maybe this will require several posts to cover any aspect of it. Let's start with an image :
Each voice of EFP has its exclusive, independent "resonator block". Each resonator block is made of a set of 16 Universal Helmholtz Resonators.
Helmholtz resonators are "hollow bodies" (resembling a sphere in some cases) with only one embouchure/hole and when an air jet is sent inside it, sound is produced by the oscillation of air moving by pressure and depressure (standing waves) at the hole.
"Universal" means that the cylinder length can be adjusted, changing the volume of the body and varying the pitch of the single resonator. In a resonator block, each cylinder length can be automated/modulated.
In addition, each resonator embouchure/hole has its own independent open/close valve. This valve aperture can be automated/modulated.
A full set of 16 Universal Helmholtz Resonators constitute a single "resonator block". An advanced, easy to use system has been developed to let users control each of the 16 + 16 UHR valves (per voice) with just the turn of a single knob.
PS : How the air-oscillation is triggered
When an air jet is sent to the UHR hole/aperture, some amount of time is needed for the air *inside* the resonator to reach the pressure threshold to activate the pressure-depressure oscillation. It's a certain amount of time needed by the air jet to "fill" the resonator volume.
If the internal volume of one resonator is small (= it resonates at higher frequencies), it will require a certain time for the air jet to fill that volume. And, if the internal volume of another resonator is bigger (= it resonates at lower frequencies), it will require more time for the air jet to fill that volume and start the oscillation.
So, in EFP, this aspect is preserved and smaller UHRs will have a lower "response time" (a sort of "mechanical latency" - that has nothing to do with electronic latency itself) than other bigger UHRs. Although this response timing difference if very small, it is measurable and also slightly perceivable.
End of part 1...