Further to the agony I hear in Vallotti for Variatio 25, I find there’s more to it than just my subjective hearing. There’s an article in the Riemenschneider Bach Institute journal, Vol. 28, No. 1/2, 1997 by Timothy Smith titled: That “Crown of Thorns”. Here is the opening paragraph:
It was the habit of Wanda Landowska, one of this century’s more brilliant interpreters of the Goldberg Variations, to refer to Variatio 25 as that “crown of thorns.” As a renowned performer, Landowska was entitled, of course, to plead Christ’s passion if only to soothe her own angst when it came to the interpretation of this Herculean cycle. But the demand of Variatio 25 is spiritual, not technical. Landowska 's presentiment of agony must have been a consequence more of what was said than how. In that sense Landowska’s crowning insight may have been for anagogical undertones that appear to have reverberated within the mind of the composer, Johann Sebastian Bach, himself. What are these undertones, and how did Landowska come to hear them?
So, she is using equal temperament but is also musically agonised. What am I saying here? Essentially, that this is a very non-trivial movement with enormous depth, not just flashly fingerwork.
The paper is available on JSTOR if you have access:
THAT "CROWN OF THORNS" on JSTOR
If not I can send people a copy on request. PM me.
It’s not about tuning, but about deep symbolism in that variation. I know some people disdain this sort of writing and say that it’s easy to invent all sorts of things about Bach’s intentions, but I think there is something in this sort of topic.
This may not actually be the right forum for this sort of discussion, and maybe I just musing to myself out loud, but please forgive me if you think I am somewhere down in the back paddock of the 30,000 hectare sheep farm (of which we have many!).