From their myspace page: 

"ZX Spectrum Orchestra have been locked away in the lab writing code. They use no midi, no samplers, in fact, no instruments other than Sinclair hardware and peripheral devices. For instance, vocals on tracks are supplied by the Currah µSpeech. An early speech synthesizer built for the ZX Spectrum, it explores the found poetry of basic keyboard commands. "

If you like this, then cram some some more of their pure electronica into your face:

http://www.myspace.com/zxspectrumorchestra

It's industro-binary geek-rock madness. 

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