ROCKPORT — The string quartet is not as old a technological advance as some — gunpowder, movable type, and double-entry bookkeeping all predate it — but it is old enough to be taken for granted. That is probably why the sound of the string quartet, paradoxically, does not sound as dated as the electronic sounds it is paired with in Leon Kirchner’s String Quartet No. 3, the centerpiece of the Parker String Quartet’s concert on Friday at the Rockport Chamber Music Festival.

In Kirchner’s defense, those electronic sounds are vintage 1966, epochs ago by computer science standards. And, really, no matter: The quartet is a great piece, a generous dose of the sort of muscular, pragmatically emotive modernism that Kirchner, who died in 2009, at 90, could do better than almost anyone.