Warm brown-leaning roar at 3.7 in seven-second cycles with a fast 0.7 Hz flicker
Preview plays right here. The generator adds a sleep timer, full controls, and WAV export.
Furnace is the roar of a gas burner or a basement boiler kicking on, holding for a few seconds and easing off, with a fast flicker inside the flame. It is warm and enveloping, and the flicker gives it a restless, physical quality that steady presets do not have.
The color is 3.7, well toward brown. The envelope rises over 1 second, decays to 70 percent, holds for 4 seconds and releases over 2, a cycle of about seven and a half seconds. A triangle pulse at 0.7 Hz flickers the level roughly every 1.4 seconds on top. Grey EQ is off.
It suits people who like the feel of a heating system cycling on a cold night. Diesel Engine is the faster, darker mechanical throb at 4, and Distant Thunder in the nature category is a similar slow-cycle brown sound with a much softer attack. It is a daytime and evening sound more than an overnight one.