Cross-Grainger free music machine

The Cross-Grainger free music machines are a series of composing devices devised between 1945 and 1961 in White Plains, New York, by the American physics professor Burnett Cross, born in New York in 1914 and died in 1996, and by the composer Percy Grainger. Both sought to realise the idea of a free music built on sliding sounds, the so-called glissando tones.

The first prototype, dated between 1945 and 1948, used three Melanettes, small monophonic electronic keyboards later replaced by Solovoxes. They were tuned a sixth of a tone apart and were controlled from the keys of a silenced pianola piano. This microtonal tuning produced an approximation of the sliding effect they were after. It was the only one of the machines ever completed.

Later models explored other technologies. The Reed-box Tone-tool, built between 1950 and 1951, used harmonium reeds tuned in eighth-tones and actuated by perforations in a roll of brown paper. The 'Kangaroo Pouch' system, from 1952, moved a paper roll with cut-out graphics sewn to its sides, which mechanically actuated the oscillators. The final machine, begun in 1953, used transistorised oscillators and lines drawn in erasable ink on plastic film, read by photoelectric cells, in a procedure specific to what is called drawn sound. None incorporated timbre control, which was left pending.

Today the Grainger Museum in Melbourne preserves the Reed-box Tone-tool, the 'Kangaroo Pouch' system and part of the final machine, most of which was lost during transport. Cross restored them over several visits. The museum also holds a machine from 1950 in which a swanee whistle and two recorders are operated by a perforated paper roll.