Franz Schubert’s String Quartet No 15, written in 1826, stretches over a symphonic arc that lasts some 50 minutes, while intimate, insular utterances place the monumentalism of that structure in question just as it’s being erected. Then there’s the apparent balmy warmth of Schubert’s melodic writing, forever a chess move away from revealing a dark, haunted core. These are paradoxes with which any string quartet bold enough to tackle Schubert’s magnum opus must deal, and which the Takács Quartet comprehensively nail: the bigger picture emerging as, on another level, melodies pixelate and harmonic sequences fragment, phrases coming at you from out of the shadows. This is Schubert playing of the highest order.