The sound generator is based on a master oscillator with a MK50240 top octave divider chip, so it divides the generated oscillator square wave into the 12 semitone notes of an equal tempered octave. The left range split can have monophonic bass sound with extra volume and percussion attack control.
SOUNDS there are basically 3 sounds t"CELLO", "VIOLA" and "VIOLIN" you can mix a combination of three string sounds.
The String Melody II features also five different ensemble effect variations with pretty strange name: "O, ACC., SOLO, ORCH., and ORGAN"
O: chorus & mixer
acc.: accordion as plain out (w/o chorus) & mixer
solo: fast LFO - tremolo (FM), low LFO - vibrato (AM) w/ chorus & mixer
orch.: full orchestra w/o mixer and bass
organ: only low LFO chorus & mixer