There's nothing at all wrong with Maurizio Pollini's 2009 performance of Bach's Well-Tempered Clavier, Book 1. The Italian pianist's intellectual lucidity, interpretive clarity, and technical virtuosity are apparent in every prelude and fugue, and his probing insights and penetrating analysis inform every note. However, there is almost nothing right with the sound quality of the recording. The piano sounds too distant, making it hard to hear precisely what Pollini is doing, but oddly, the ambient sound is too present, making every extraneous noise too loud. One should not hear the pedals being pressed and lifted, much less the clatter of the hammers and the twanging of the strings above the sound of the music. Worse yet, one can hear what sounds like every breath Pollini takes nearly as loudly as every note he plays. These are all grievous flaws that should have been eliminated, and their presence fatally undermines the brilliance of Pollini's performances. A reengineered version of these performances would be most welcome, but the present recording is so flawed that it virtually destroys Pollini's playing.
In his recording of Bach's 48 Colin Tilney, unlike his fellow competitors in the same repertory, plays both a clavichord (Book 1) and a harpsichord (Book 2). Why not? Bach's title for the first book of 24 preludes and fugues, The Well-tempered Clavier leaves both this issue and that of tuning wide open. The clavichord was a favourite instrument of Bach's, so was the harpsichord and the organ; indeed, I am sorry that Tilney does not include a chamber organ since some of the pieces, the E major Prelude and Fugue (Book 2), for instance, seem well-suited to it. Tilney's performance of the 48 differs again from almost if not all others in the sequence which he adopts in playing the preludes and fugues. But an apparently random approach is in fact nothing of the kind, but one that is directly linked with tuning. We know that Bach himself was a master in matters of tuning as he was in all other aspects of his craft. What we do not know is the exact nature of his tuning.