Several ensembles have established international reputations by playing Béla Bartók's six string quartets with authority and strong character, notably the Juilliard, the Takács, and the Emerson, and countless others aspire to achieve equal renown with these celebrated works. Because this cycle is essentially the bible of modern writing for string quartet, it has become a test for string players, not least because of the many technical challenges it presents, but more importantly for the expressive demands Bartók makes on individual players and the ensemble as a whole. There's little doubt that the Hagen Quartet has the skills to deliver this music with accuracy and the physical stamina to play with the steadiness such difficult music requires. However, this is in many places a surprisingly subdued interpretation of the quartets, perhaps more oriented toward the melancholy strain that runs through Bartók's music, rather than toward the vigorous or caustic sides of his genius. To be sure, the Hagen Quartet ignites in crucial places, and when it has to be direct and forceful, it gets the job done. But the feelings this set communicates are not quite bracing and energetic like the Juilliard's three recordings, fiery or passionate like the Takács' set, or incisive and driven like the Emerson's, but pensive and brooding, and the general tonal cast of these performances is of a grayer shade or lower energy in spots than one might expect. This, naturally, is fairly suitable in the string quartets, Nos. 1, 2, and 6, which are among Bartók's more depressed expressions, but it isn't especially desirable in Nos. 3, 4, and 5, where a brighter, harder edge is necessary. Listeners will certainly derive much pleasure from particular movements in these performances, and may even enjoy some of the quartets separately from the set, but it will be difficult for them to rank the whole album among the greatest Bartók recordings.