For those who have ears to hear, these pieces tell the tale of a man who had hope, dignity and the possibility of joy crushed out of him by the years of Stalin's terror, and then by the siege of Leningrad. While he was obliged to compromise some of his public large scale music in the name of socialist-realism, simply in order to survive as Stalin's pet composer, he managed somehow to preserve the highest degree of artistic integrity for his chamber music.
For me, the special quality of the Fitzwilliam's performance is that they are transparent with regard to the composer's original intentions. The beautiful parts are played beautifully, the furious parts furiously, but all the parts are bought into an integrated whole that you can't help but feel would have satisfied the old man tremendously. I have heard various other performers attempt these works, with more or less success, but it seems that they always come with baggage and an agenda to press. The Borodins play-up the Russianism, the Kronos overdo the modernism, etc.
As for the quartets themselves none of them are minor in their scope or ambition. They all have something quite specific to say about the nature of human existence and folly, as masses and as individuals. There are brief moments, more perhaps towards the later quartets, where bitterness and dark intimations of mortality give way to a peaceful acceptance, but always briefly and provisionally. There are no happy endings, only surrender to the inevitable, alone in the knowledge of the truth of what we are and what we have been.
I could perhaps talk about the quartets one by one, but all are deep and wide enough that one's comprehension of each must grow indefinitely with repeated listening. Left alone with these disks on a desert island a true music lover would never be bored, but they might need to dash their own brains out with a coconut for light relief.