The CD booklet calls The Music Teacher an opera, but when this collaboration between composer Allen Shawn and his brother, playwright-actor Wallace Shawn, was premiered by The New Group in New York in 2006 it was called a “play/opera”, which is probably closer to the mark. The complex one-act scenario concerns a liaison between the title professor and a teenage student, told in prologue and flashback, with the opera co-written by the two serving as the extended centrepiece. The structure is, to put it charitably, a mess – to the extent that it doesn’t even work within the generous parameters of experimental theatre.

What does work is the prevailing mood of gentle melancholy nostalgia in Shawn’s music. There’s a reflective, madrigal-like “Round” as Jane remembers her experience and a not-very-rocking “Rock Song” for Jane and the other students. In the concluding flashback, in which Mr Smith swiftly and improbably gets into a series of three sexual encounters, there is a sultry torch song by a hotel lounge singer, an awkward reunion and belated semi-consummation by the two lovers, and a reprise of the duet from the opera.

The opera-within-the-play/opera seems intended as a somewhat ironic parody with its love triangle between Alcimedes and Aeola (Mr Smith and Jane) and Chronilos. Wallace Shawn’s libretto is graceful and suits his brother’s music but the satire isn’t pointed or exaggerated enough to be very funny. The would-be irony of blandly eating breakfast alternating with epic operatic themes doesn’t provoke the intended guffaws and merely seems self-consciously clever.

Yet the music is largely attractive, as in “When did the clock strike midnight?”, a lovely aria in the vein of restless sadness, and a quite beautiful love duet, “The night stands still”. The singers are excellent, particularly Sarah Wolfson as Jane/Aeola and Jeffrey Picón as Mr Smith/Alcimedes, who performs his Locket aria and Bird aria very well indeed. Wallace Shawn and Parker Posey bring a natural intimacy and simplicity to the spoken sections, scaled for home listening.

The Music Teacher has had a tortuous history, revived from an unfinished work of 20 years earlier for its 2006 premiere. Despite the structural awkwardness and inert dramatic pacing, Shawn’s wistful, tonally centred music successfully conveys the atmosphere of loneliness and regretful melancholy.