Works for string quartet by Musicians from Marlboro and Daedalus Quartet:Haydn: Quartet in G Major, Op. 17, no. 5Lerdahl: String Quartet No. 1This week, we’ll hear a pair of string quartets—one from the father of the genre, and the other from a relative newcomer.We begin with Papa Haydn, the author of nearly 70 string quartets, and—by broad consensus—the father of the form. Haydn’s quartets are as varied as they are numerous.The selection we’ll hear today is Haydn’s 22nd string quartet, opus 17, number 5. The piece plays for 17 minutes, beginning cheerful and sunny, passing through a cloudy patch, and emerging—in the finale—in a blaze of joy. Performing it are players from Musicians from Marlboro.Then we’ll move to 21st century quartet writer: composer Fred Lerdahl, performed by the Daedalus Quartet. The germ of the idea that fueled the three Lerdahl quartets is the chord heard at the very beginning of this first quartet. It flashes by in about a second, but within that chord lies the source of all the ideas that Lerdahl develops throughout the entire twenty-plus minute work, through a technique he calls “expanding variations.”One hears flickers of the chord throughout the piece, but the form is less a literal “theme and variations” than an organic expansion; from that brief chord, the ensuing variations expand, each one and half times the length of the preceding one.We start with the seed of the quartet genre itself: Haydn.