2017 Aug 27: Preludes in C

August 27, 2017 10:30

Prelude in C, "Well Tempered Keyboard" Book 1, No. 1      J.S. Bach (1685-1750) [ PIANO]
Prelude in C      F. Chopin (1810-1849)

"I Have Peace Like a River"

Improvisation

We continue our series ’water preludes’ (to harmonize with Sandy’s sermon series), but this week I’m resorting to a dubious pun, as we're in the process of moving to Highland and all my resources are in boxes. Consequently this week I’m relying on the questionable pun that ’Bach’ means ’Brook’ in German and therefore that qualifies as a ’water prelude’!

So kindly bear with a bit of mathematical music theory. Two notes at the same time are called an ’interval’, and two musical intervals in particular are profoundly fundamental to music across time and cultures. If you’ll recall your "do-re-mi’s", our two fundamental intervals are the ’octave’ – from ’do’ through re, mi, fa... back to ’do’, and the other is the ’fifth’ — if ’do’ = 1, then ’re’=2, ’mi’=3, ’fa’=4, and ’so’=5 ... so from ’do’ to ’so’ is a ’fifth’.

Remarkably, Pythagoras (5th century BCE — or the school he founded) figured out that these two fundamental musical intervals have a basis in mathematics/physics. We now know that musical pitch is the result of regular vibrations of air. In the case of the ’octave’, the ratio of vibrations per second is 1:2, for the ’fifth’: 2:3 – exactly as Pythagoras figured out over two millennia ago.

Furthermore, it’s not possible for a keyboard instrument, regardless of tuning system, to have all its octaves and fifths in tune at the same time. Pythagoras also demonstrated this anomaly in the 5th century BCE. (Strings, brass and woodwinds can tune on the fly so this is not an issue for them.)

So if we fast forward to the Renaissance when keyboard instruments were becoming important, their solution was a keyboard tuning system called ’just’ in which a few keys (with a couple sharps and flats) are in good tune and the rest unusably out of tune. But over time composers wanted to use more keys, so the standard keyboard tuning system evolved to the ’mean’ tuning system in which more (but still not all) keys were usably in tune (but not as in tune as the ’just’ system).

By the time of Bach in the early 18th century, the idea of all twelve keys being usably in tune was in the wind. And so the idea of ’well-tempering’ was proposed (’tempering’ is how you fudge the Pythagorean anomaly) — so a ’well-tempered’ tuning system is one in which all the keys are usable, although some keys like C major might be more in tune than others. (Today we use a system called ’equal-tempering’ — all 12 keys are equally out of tune, but we’re used to it.)

"Well-tempering" was cutting-edge musical technology in Bach’s day, and ever the pedagogue he decided to demonstrate its possibilities. So he wrote the "Well-Tempered Keyboard" – a Prelude & Fugue in each of the 12 major and minor keys — 24 in all. And he had such a good time doing it he wrote a second set, so we have two volumes. And it is much more than a demonstration of a new tuning system: ever the pedagogue, Bach composed it to be an encyclopedic demonstration of the musical styles and forms — English, French, North German, South German, Italian, Polish – from centuries past to his present day (all through his own stylistic lens, of course).

The first prelude in the first volume of the Well Tempered Keyboard is especially famous. Using a simple ’strumming chord’ motif it includes jazz chords that won’t be invented until centuries later. (And it's suggestive of rippling water! <grin!>)

The "Well Tempered Keyboard" has had an enormous influence on subsequent composers: Mozart, Beethoven, Brahms, etc. all studied it, and even Stravinsky would play from it to ’warm up’ for a composition session. Other composers have been inspired to write their own sets of preludes in all the keys, including Chopin, whose first prelude in his own set of 24 preludes in all the keys is also in C major, and also based on a ’strumming chord’ motif — clearly an homage.

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