At first glance, the student work of a 20th Century American and one of an 18th Century Austrian’s late masterpieces might seem uneasy bedfellows: Barber’s first and only string quartet is passionate and restless, while Haydn’s is typically sunny and elegant. Yet they both have something fundamentally in common: their fame rests almost entirely on their slow movements. The centrepiece of Barber’s quartet is best known in its orchestral guise (Adagio for strings), famously used on the soundtrack of the film Platoon; Haydn’s Adagio opens with one of the most memorable melodies he ever wrote, originally written in 1797 as the theme to a patriotic song for the Austrian ruler Franz II (Gott erhalte Franz, den Kaiser); it was then taken up as the national anthem of the Austrian Empire, and subsequently by the Germans for theirs (Deutschland, Deutschland über alles).

Barber: String Quartet Op. 11
Molto allegro e appassionato - Molto adagio: Molto allegro (come prima)

Samuel Barber is often described as a neo-Romantic, but this is to damn with faint praise: as you will hear from the opening bars of the B minor string quartet, his musical language is far from the anodyne blandness that the term implies. Here is a voice which has absorbed the tumult of the early 20th Century, assimilated the influences of Schoenberg and Stravinsky and forged a highly distinctive voice.

The first movement opens with a surging unison motif (which recurs in various forms throughout) and is characterised by frequent changes of tempo and metre with little real sense of a fixed tonality. The prevailing mood of anguish is shot through with moments of serene calm: after the opening motif makes a (slightly extended) comeback, a brief ‘bridge’ passage recalls it almost longingly before melting into a theme of wistful beauty. The movement goes through several other changes of mood, reaching a huge climax marked Più largo (slower) followed by a period of reflective ‘calm after the storm’. The first section of the movement is then recapitulated, but the movement ends eerily quietly.

The famous Molto adagio needs little introduction. Its key signature is of five flats (B-flat minor) and the tempo very slow, which lends the movement an intensely mournful and static feel. The comparatively simple melodic material is brought to a shattering climax, before the music subsides and finally dies away. Barber indicates that the final movement should follow directly on from the Molto adagio: the ‘surging’ motif from the very beginning is hinted at quietly, then reappears with full force. The last movement is really a very concise reappraisal of the first: familiar figures and episodes recur before a frenzied Presto propels the quartet headlong to its conclusion.

Haydn: String Quartet Op. 76 nr. 3 (Emperor)
Allegro (moderato) - Poco adagio cantabile - Menuetto: Allegro - Finale: Presto

Though not the father of the modern string quartet, Haydn did more than anyone to establish its place at the heart of Western music. For their sparkle, polish and sheer inventiveness, his 68 published quartets stand supreme. The six opus 76 quartets are the last major examples Haydn composed (there are two op. 77 and an unfinished op. 103) and as such reflect a lifetime of writing in the medium. The third of these, the Emperor quartet, owes its name to its famous slow movement, rather than to any particularly imperial quality; it is, however, a uniformly fine work, and the other three movements alone more than justify its regular performance.

The quartet opens in C major in a jovial vein, and indeed the mood of the whole movement is warm and untroubled. There is a certain poise to the music, strengthened by the use of frequent trills and dotted rhythms, perhaps harking back to the more formal Baroque era. The second movement (in G major) is a theme and set of four variations on the Emperor theme. After the initial statement of the theme (in the first violin), each instrument takes it in turns to expound the theme: in the first variation, the second violin; in the second, the cello; and in the third, the viola, before all the instruments come together again for the final variation and a rousing final statement - ending with a surprising hush. The minuet trips along, in C major once more, with its contrasting trio in A minor, and does nothing to prepare us for the fierce finale: in stark C minor (where, in mere mortal hands it would be back to C major again), it opens with strong hammer-blow chords in the strings (double-stopped in the first violin). The mood is tense, intensified by scurrying triplet figures, and rushes nervously on - until just before the end, the sun suddenly comes out again. After a dramatic pause, we are back in C major and the movement ends quietly, but in high spirits.