The Keller Quartett sets the famous Molto adagio from Samuel Barber's String Quartet op. 11 between the two string quartets of György Ligeti. In the mid-20th century the two composers stood at opposite ends of the aesthetic map, and the album puts that distance to work. "Ligeti was all about leaving what for Barber was solid home", writes Paul Griffiths in the liner notes, while hearing a gesture of lament common to both.

The Budapest ensemble is led by violinist András Keller, with Zoltán Gál on viola and Judit Szabó on cello. It recorded the first Ligeti quartet and the Barber in June 2007 at Radio Studio DRS in Zürich. That session marked the first anniversary of Ligeti's death. The Second Quartet followed in October 2011, by which time Zsófia Környei had replaced the long-serving János Pilz as second violin. Peter Laenger was the engineer and Manfred Eicher produced.

Ligeti wrote his First Quartet, Métamorphoses nocturnes, in 1953 and 1954, before leaving Hungary, and its debt to Bartók is plain. It runs as one continuous movement in seventeen sections, with warped dance rhythms, slapped cello pizzicato and, near the end, a haze of harmonic glissandi. The Second Quartet of 1968 has five short movements of sharply different motion. In Sostenuto, molto calmo the music slows almost to a standstill, and Come un meccanismo di precisione is a ticking pizzicato machine before the violence of Presto furioso, brutale, tumultuoso. In between, the Keller play Barber's Molto adagio of 1935 and 1936 with almost no vibrato, briskly and without sentiment.

Reviewers took the pairing as a provocation that pays off. In The Times, Richard Morrison called the readings "tremendously abrasive, intense performances" and noted that the Second Quartet "still sounds avant-garde 45 years on". David Kettle in The Strad praised the "glassy purity" of their sound, with each instrument heard "in individual clarity". He heard in the Barber a simple, moving statement stripped of mawkishness. Dominy Clements at MusicWeb International preferred the Keller to the Arditti and Parker recordings, especially in the Second Quartet.

CD, ECM New Series 2197, first released in June 2013, with liner notes by Paul Griffiths.