Fictional electronic keyboard and composing tool that automatically harmonizes the melody played, from Lloyd Biggle Jr.'s short story "The Tunesmith." It first appeared in Worlds of If magazine, August 1957. Biggle actually had a PhD in musicology!
In the story, composer erlin Baque is adamantly against using one, even though he composes ad jingles ("Coms") in a future where, like the 1993 film Demolition Man, ad jingles are the ONLY music people listen to.
He slammed his fists down on the keyboard, and shouted above the shattering dissonance. "I will not rent a harmonizer. I will not turn my arranging over to hacks. If a Com goes out with my name on it, it’s going to be composed . It may be idiotic, and it may be sickening, but it’s going to be done right. It isn’t much, God knows, but it’s all I have left."
Compose something. You’re not a hack, like the other tunesmiths. You don’t punch your melodies out on a harmonizer’s keyboard and let a machine harmonize them for you. You’re a musician, not a melody monger.