Steel Door Slam

How it's made

Source

a heavy steel leaf hits its frame; a 1 ms attack and 22 ms filtered noise contact excite the panel. A 65-110 Hz, 240 ms pressure thump carries the mass without an artificial sub drop.

Body

welded sheets and stiffeners have inharmonic modes at 78, 121, 193, 281, 417, 613, 887, 1283, 1849 and 2671 Hz. Low modes have 1.6-2.4 s T60; upper modes die in 0.25-0.8 s. Slightly split middle modes produce beating; a broad 150 Hz cavity adds the hollow door interior.

Latch

a separate 3 ms bolt contact follows 48-80 ms after the slam, followed by two quieter rebounds. Short 0.8-3.6 kHz modes make a clack, not a second full door impact.

Space

31/47/73 ms wall reflections and a dark diffuse room tail place the door in concrete. Space is intrinsic to this bunker/cell concept; the sealed preset keeps it close and damped.

Envelope

upper modes and contact noise die first, leaving a low hollow metallic ring. The final 180 ms fade ends near 2.5 s by default, after the physical decay, without an abrupt cutoff.

Variation

seeded tuning varies by 0.6 percent and latch timing by 5 ms. Mass scales panel and cavity frequencies; damping, latch strength and room amount distinguish four usable door types.

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