The home-built noise box is the noise underground's answer to the synthesiser: an electronic instrument the player builds rather than buys. At its simplest it is a collision of square-wave oscillators, feedback networks and distortion, wired onto a circuit board and housed in whatever was to hand, a biscuit tin, a junk enclosure, a metal box studded with bolts and contacts. There is no keyboard and usually no calibration; the controls are whatever the builder fitted, and the instrument's range is whatever its faults allow. The Bureau files it as a technique rather than as equipment because there is no model to point to. Each one is unique, and the building is part of the playing.
The technique is distinct from two others filed nearby, and the distinction is the reason it has its own page. Contact microphone work amplifies the vibration of an object the player did not build; no-input mixing coaxes feedback from a commercial mixing desk used against itself. The home-built noise box is neither: it is a purpose-made sound generator, an oscillator instrument whose circuit is the composition. Its closest relative is the circuit-bent toy, the short-circuiting of a mass-made electronic device into an unstable instrument, and the two traditions overlap in the workshop.
The Japanese harsh-noise scene took the method furthest. Masami Akita built and rebuilt his own rigs across the Merzbow catalogue, and the custom junk-electronics box, the tin-can oscillator collision sometimes built collaboratively in workshops, is part of why the Kansai and Tokyo equipment-customisation tradition produced a sound the European and American scenes reached differently. The Gerogerigegege and a long roster of Japanoise players worked from self-made or heavily modified electronics rather than off-the-shelf gear. The tradition continues worldwide: the DIY noise device, the circuit-bending workshop, the hand-built synth sold in ones and twos, all descend from the same principle the Bureau files here, that in noise the instrument and the instrument-builder are the same person.