The Concerto for String Quartet by Louis Spohr is a rare example of a genuine “String Quartet Concerto,” in that the quartet is treated as its own voice, a single unit featured alongside the full orchestra, rather than a concertino group that you’d hear in something like a concerto grosso. It’s rather fitting that Spohr produced a work such as this one, because he also composed 36 different string quartets. It’s our Evening Masterwork tonight at 7 on Classical WSMR 89.1 and 103.9.