Pink-warm noise at 3.2 gated by a square pulse every two seconds, a mains buzz
Preview plays right here. The generator adds a sleep timer, full controls, and WAV export.
Electric Hum is the buzz of a transformer or a fluorescent light ballast: a hard-edged on-off pulse over a warm noise bed that reads as electrical rather than mechanical. The square shape gives it sharp corners, and the rapid envelope turns it into a buzz rather than a swell.
The color is 3.2, slightly warmer than pink. The envelope loop is extremely short, attacking in 0.05 seconds, holding for 0.3 at 90 percent and releasing in 0.1, so it cycles roughly twice a second. A square-shaped pulse at 0.5 Hz gates the level on and off every two seconds on top of that.
It is mostly used for sound design and by people who find the buzz of old electrics oddly soothing. Diesel Engine is the low, chugging equivalent, and Static TV in the experimental category is a faster, brighter version of the same gated idea at white.