This two-disc set of Langgaard string quartets isn't titled "Complete String Quartets" for a reason. Number 1 is not included, having been reworked into Numbers 4 and 5, and an A-Flat Major Quartet from 1918, never previously performed, is also missing. To which I can only ask: Would it have killed you to include them anyway? So what we have is Numbers 2 through 6 and a set of variations on "O Sacred Head, now Wounded." They are exquisitely performed by the Kontra Quartet, a Danish ensemble with a Hungarian 1st violinist (Anton Kontra), whose complete cycle of the quartets of Vagn Holmboe (Don't know him? You should!) are a landmark in modern quartet writing and performance. Here, in the Langgaard quartets, they make the kind of beautiful music so well known from this composer. Langgaard is variously prickly and lyrical, and it's in the lyrical moments that he can become, well, a bit dull. But as ever, your mileage may vary in this.
For those who have already experienced his signature work, "Music of the Spheres," his symphonies (Da Capo's new set with Dausgaard conducting is exemplary), and his opera "Antichrist," these quartets will be a welcome addition to your collection.