The mood of Friedman’s two quartets, which combine romantic emotion with an absence of forgiving softness, gives the strings a chance to try out two things they do especially well, namely: sweep around lush corners and hit a precisely sharp point in space with tart and trembling accuracy. The last moments of the second movement in “String Quartet No. 2” are sweet without being oversweet, melancholy without bursting into tears, overwrought but bearable — everything carried up to the edge of intense feeling and left quivering. At the end of each quartet we hear the work again, remixed by Matmos, who brought Friedman in to help with their 2006 release, The Rose Has Teeth in the Mouth of a Beast. Now the strings stammer and capitulate to squelches. These remixes are total changes of pace, but excellent palate cleansers.