Yamaha CX5M Music Computer

The Yamaha CX5M, introduced in 1984, is an MSX-standard computer built around a Yamaha FM synthesizer. It was one of only two MSX machines ever sold in North America (alongside Spectravideo's), and it was marketed not as a computer but as a Music Computer — sold in music stores, not computer shops. The machine boots to Microsoft MSX BASIC; a built-in SFG-01 module carries the 8-voice, 4-operator YM2151 FM chip (the voice architecture family of the DX9/DX21/DX100), with stereo audio outputs, a connector for Yamaha's YK-10 music keyboard, and MIDI ports. The whole point of the machine was making music, and the QWERTY computer keyboard was the primary composition instrument.

Music was made through software cartridges rather than piano-style playing. The YRM-101 FM Music Composer cartridge presented a musical-stave editing screen where the user entered notes step-time from the QWERTY keyboard — no real-time recording. The YRM-104 Music Macro cartridge made the synthesizer programmable from BASIC with commands like _INST(1) and _PHRASE(1,"cdefg"). YRM-102/502 let you program banks of 48 voices; YRM-103 was a DX7 voicing cartridge that gave the notoriously cryptic DX7 a real screen for editing patches. First CX5M units could only send MIDI out (to a DX7); the CX5M II / CX7M-128 (1986) added the SFG-05 module with MIDI input, and the FB-01 (1986) was essentially the SFG-05 in a standalone box.

The CX5M sold for about £1,000 in the UK in 1985 and was a commercial niche product that failed to crack the US market. Its cartridge software and ROMs are preserved and emulated today; a complete CX5M set is in the collection of the Musée des Instruments de Musique in Brussels, and another is held by the HomeComputerMuseum in the Netherlands.