Probably the only demoscene production for an unexpanded Sinclair ZX Spectrum 16K. Made by Gasman/H-Prg, music is using ROM routine via music made in Gasman's Romford Tracker written in Javascript.
What can be done with regular ZX Spectrum 48K and its BEEPER in... recording studio. :) The only instrument/sound-source and the only sequencer: ZX Spectrum 48K (BEEPER). ***The heavy post-production has been used.*** Recording-studio effects: track-by-track recording / filters / phasers / choruses / flangers / ...