The Icelandic baritone Kristján Jóhannesson sings Beethoven! No, not music by Beethoven, but the character of Beethoven in the world premiere of a chamber opera that promises to mix fact and fantasy with madcap abandon. The composer is grumpy, it seems, that orchestra musicians can’t stick to his tempi. Enter the Mälzel brothers with their spanking-new invention, the metronome, accompanied by their eye-catching assistant Genia, a mechanical whiz in her own right. Oh, and then there’s the automated “Panharmonicon,” consisting of 259 instruments. For the record, the real Beethoven apparently composed his Technicolor tone poem “Wellington’s Victory” for just this monstrosity, which actually existed. —M.G.