Hardware limitations on NES audio

NES music was limited to the five monophonic channels of the Ricoh 2A03, so a whole arrangement could sound at most five notes at once.1

Convention settled each channel into a role: the pulse waves carried melody and harmony, the triangle carried the bassline, and noise and samples carried percussion.12

Composers used workarounds to get past these limits:

  • Fast arpeggios on one channel imply a chord.2
  • Pitch-bending the triangle turns the bass channel into percussion.1