Singing this Note is IMPOSSIBLE!

Funny how things will dovetail into others...many years back I read a fair amount about resonance with regards to automotive/motorcycle engine intake tracts. Neat thing there, since pretty much all consist of plastic parts these days, is that the resonance of the materials directing the airflow can be tuned to improve intake charging. We tend to think of the air going into a motor as a steady pull but it is actually in the form of discrete pulses as the intake valves open and close. That sets up pressure waves upstream in the tract, which, as you've shown, can either enhance or interfere with cylinder air charging. It's a subtle effect on a powerful motor, but if you're trying to wring every bit of performance out of it, you will consider it. When the intake resonance matches the cylinder charging requirements at peak power it can give it a noticeable bump. Oh and that weird ultra-low frequency drone you get when you have one back window down in most modern cars? Resonant frequency of the cabin, being expressed by the roof panel, as they aren't as stout as they used to be. The air trying to come in the window is creating overpressure in the cabin, the roof panel swells just a bit, then springs back, expelling air back out but creating a low pressure draw through the window, starting it over again...it's doing the same thing the jug is when you blow over the opening...at its natural frequency.