Pipe Organ

The mouth cut through and turned on its side, one cycle over two seconds: the air moving through the mouth (yellow) bends the jet at the flue; the bend grows on its way across and steers the jet into the pipe or out of it at the labium.

The pressure across the mouth against the air’s speed through it. Where they rise and fall together (the loop leans ↗) the jet feeds the pipe; the steps are the jet flipping across the labium.

The chest’s pressure over the last eight seconds: chords drain it and it sags; a flexible wind dips and rings; the tremulant pulses it.

Markers: the resonances of the last key’s pipe, every harmonic for an open pipe, only the odd ones for a stopped pipe.

Watch the attack: in the chiff the upper modes speak before the fundamental, then the jet settles into a steady stack of lines. A stopped pipe draws only the odd ones.