Thank you. I guess my question is can I separate the impeller from the rotor and still have enough pressure. So an impeller that is not also functioning against the stator and then another motor that controls the speed of the opening of the ports.

Dear All, I am new here. I was curious about measurements in cubic meters per minute or hour of a mid-sized siren. The reason I ask is because I am considering a design of a homemade siren where the frequency is decoupled from the amplitude, by having an impeller (perhaps with a ducted fan) separate...