Last time we considered the early development of the symphony and the string quartet. The obvious difference between these two forms is that while the symphony orchestra has undergone manifold changes in the intervening centuries since Haydn was active, the quartet has continued to comprise the same four trusty instruments. Therefore the endurance of the string quartet has been, in a sense, far more meaningful than that of the symphony orchestra. What is the secret of the quartet’s success? Why has it survived when other formats of yesteryear, popular in their own time – one thinks for instance of the madrigal, the trio sonata and oratorio – have more or less fallen into disuse, though some determined souls doubtless continue to persist with them? Of course there are a variety of reasons, many cultural, many technological. However there are purely musical reasons as well, and it is worth briefly considering what these might be.
A critic recently remarked, in an interview with Philip Glass, how the quartet is particularly well-suited to intimacy and introspection. It is arguable that this has made it ideally placed to exploit the trend for more recent composers such as Debussy, Bartok and Shostakovich to use their works to convey moods of darkness and disturbance reflective of the often troubled and tumultuous times in which they lived. In the early days of the quartet it was not the fashion to write music to convey mood as such; however this began to change as the nineteenth century progressed, and the quartet was found to be sufficiently versatile to express Shostakovich’s powerful and painful cris de coeur as well as Mozart’s elegant exhibitionism. The timbral unity of the quartet is also significant; no other combination of four instruments could provide such an opportunity for the ensemble to sound as if it is speaking with one voice. One could of course make a quartet out of flute, oboe, clarinet and bassoon, but harmonically the result would remain a mixture rather than a compound, with each constituent instrument remaining easily identifiable and the harmonic blend imperfect. Alternatively a quartet of four flutes or four clarinets would have a limited range. And, while the trained ear can tell apart a violin and a cello playing the same notes at the same pitch, they are timbrally far more similar than a flute and a bassoon.
These are just a few of the reasons why string quartets continue to be the staple for modern composers such as Glass, following in the august tradition established by Haydn. Perhaps this is to over-complicate though; I admit to bias, but string instruments are the most wonderful of all musical inventions, and the quartet configures them in the most beautifully simple way, that there is something for all composers to mould into their own creation. Of course the greatness of the string sound is primarily responsible for the success of the symphonic form as well, but that risks opening up a controversy which should be saved for another day.