I am trying to remember about a bare-board sound card which plugged into the parallel port of an Exidy Sorcerer (circa 1980). The card and software ("Music System") was made by Arrington Software Service in Boise, Idaho. It had no speaker, so it needed to be plugged into an amplifier and speaker. (Your home music system would work if it had an input jack.) One could enter the 4-voice song from sheet music, or you could buy pre-compiled digital music libraries. Note that the system was polyphonic, but not stereo.
Unfortunately I don't have either my Sorcerer or the sound card anymore. I'd like to know what D/A converter the latter used. Maybe I was just ignorant, but I don't remember any other such system, with both 4 voices and the ability to type in sheet music. The editor literally looked like part of a page of sheet music.
Did other systems of the era have these features?
... scavenged around and found Mr. Arrington's 1980 brochure in a cabinet. Quoted extract:
HARDWARE -- Assembled A/D converter connects to parallel port. Simply connect an amplifier to your stereo to listen to music. ...
(sic; I'm sure he meant "D/A")
MUSIC GENERATION -- Machine language routine generates four part harmony of true frequencies over a 4 and 1/2 octave range. The routine easily interfaces with your Basic programs to add sound effects and music. Well documented.
EDITOR -- System includes a screen editor that displays the two musical staves upon which musical notes are placed. ...
It cost $40 (which today would probably be about $150). An optional entertainment add-on called Piano Player cost $15. It showed a
full-screen man seated at a piano, playing it. His motions reacted to the music being played. !! See image in exidyboy's answer. I obviously remembered it wrong.