I have been having a long think (3 months' worth on & off!) about PlugIn's post above. Very thoughtful and thought provoking.
I have been wondering for a long time why it was that Bach restricted his keyboard output (as opposed to his specifically organ output) to just a 4-octave range. The 48 preludes & fugues, the French & English suites, the 2 and 3 part inventions, all are restricted to just the 4 octaves C to C, in which Middle C (260 hertz approx) is in the centre, and he does, in most pieces, use the entire range, or close to it. The harpsichord, which I had assumed to be the instrument he was aiming at, has a bigger range than this. Normally they are at least 5 octaves. Then I bought a score of the partitas, and suddenly there we are with a bigger range! Why?
Well, thanks to Dez's Christmas present to me, I now know the answer - insofar as there is a definitive one! Much is surmised because hardly any of Bach's output was published in his lifetime and much has been copied longhand before being published much later. The answer is that they were aimed at the clavichord. This is a small instrument with very little volume to its sound. The implication here is that hardly any of Bach's keyboard works were written with the intention of being played in a concert hall. Some of it was teaching material. The 48 Preludes and Fugues were to demonstrate "equal temperament", hence one in each major and one in each minor key, in each book (apparently Book 1 was written in the 1720s, book two about 20 years later). Any performances would have been quite intimate gatherings in small rooms.
That brings us to another problem - tuning: you had to tune your own instrument! It is still possible to buy a clavichord - Morley's of Lewisham sell them and used to make them - I don't know if they still do - and the instrument comes with a tuning spanner. So the keyboard player would also have had to be able to tune his instrument to equal temperament before playing it. In that sense there is a connection between 48 preludes & fugues. The idea is that the instrument, when in tune, is OK for all of them and does not need to be retuned when switching from one key to another.
Performing any of these pieces in front of a large audience is therefore a very long way away from Bach's intentions. Playing the whole lot in one sitting on a Steinway D274 in front of 6000 people in a city some 700 miles away from Leipzig? Ludicrous! But, as PlugIn suggests, because it can be done, in the 21st century it has to be done. With regard to Schiff's performances, I think I regard him as technically very correct but, as PlugIn says, somewhat lacking in emotion. I think, from the pianist's point of view, it is a very useful yardstick to measure oneself against. All the top piano teachers these days suggest listening to virtuoso performances and, indeed, recording oneself play to see if what you produce is in itself worth listening to. With modern technology, it's easy. For under £70 you can buy a really good digital stereo recording device that is capable of writing .wav and .mp3 files to a SD card. And there is Youtube. How learning the piano has change hugely even in my lifetime!
Oh, the partitas were, apparently, written for harpsichord. That explains the greater range and, it appears (I haven't tried learning any yet!), the more virtuosic demands on the performer. Bach probably did have public performance in mind when he wrote these. They were, I understand, the last keyboard works he produced.
