Piston Pump

How it's made

Source

a crank-driven piston compresses air; each cycle has a heavy compression and lighter return. Rounded 4 ms impacts excite the cylinder; valve seating adds a separate 1.2 ms metal excitation.

Body

a 75-145 Hz pressure thump drops 25 percent in pitch over 90 ms. Damped housing modes at 310, 713 and 1190 Hz decay in 45-110 ms; small valve modes at 1450-4310 Hz die within 25-65 ms.

Envelope

3-10 complete crank cycles in 3 s. Return occurs halfway through each cycle; a 15 ms opening and 90-190 ms release shape the air hiss, with a falling 1.6-3.8 kHz spectral centre.

Layers

low filtered bearing friction supports the paired thumps, dry valve knocks and pressure hiss. No room reverb; output is high-passed at 32 Hz and low-passed at 7.2 kHz.

Variation

seeded impact levels vary by 4 percent and housing tuning by 1 percent without timing jitter. Presets change crank speed, cylinder size, valve hardness and air pressure as independent properties.

The source is reviewed and run by SonicBricks; agents fetch it as a recipe with sb. It is not published on this page.