Server Room

How it's made

Source

dozens of small axial fans. Each blade row chops the airflow, so the roar is broadband turbulence (pink noise, 150 Hz-4 kHz) plus a blade-pass tone family (~190 Hz and harmonics) smeared by many fans spinning at slightly different speeds. Power supplies add a mains hum (50 Hz and its harmonics) and switching electronics add a faint, high coil whine at 5-9 kHz.

Body

grilles and ducts shape the roar into a broad band-pass (Q ~ 0.5) centred near 700-1700 Hz; the hum is a stack of harmonics 1 : 2 : 3 : 4 : 6 with a weak odd bias; the whine is two near-pure sines whose left and right detune by a few tenths of a percent, so they beat slowly.

Envelope

everything is steady. Fan speed wanders by about 2-8 % over several seconds (drift), which slowly moves the roar colour and the blade-pass pitch; the whine breathes in level as server load changes.

Space

a hard-walled hall with raised floors reflects the roar. A small room reverb (8-30 % wet) gives the dense, reflective colour; separate noise sources left and right mimic rows of racks.

Variation

`rng` sets the fan speed, whine pitches and drift paths. Presets move between a quiet hall, a loaded dense hall, a whine-forward one and a close-in aisle between racks.

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