Bach's Well-Tempered Clavier

Johann Sebastian Bach is one of the first composers you probably think of as being "classical." Bach (1685-1750) was not actually a classical composer, but Baroque. The Baroque period, with composers like Bach, preceded the classical period, that of composers like Mozart. Bach wrote polyphonic musical pieces, such as fugues, that use multiple melodic lines in counterpoint, rather than using chords per se in harmonic progressions.

Bach was among the first composers to exploit the system of tuning called equal temperament, in which the pitches of every pair of adjacent keys on a piano or organ (for example, C and C-sharp, or E♭ and E) are equidistant. Equal pitch distances allow for greater complexity of musical development — transpositions and modulations of key, satisfying harmonies, etc. — than earlier tunings did.

Earlier tunings were more concerned with making sure pitch ratios did not involve irrational numbers, which were considered inherently imperfect. Those tunings however — such as the one described by the ancient Greek philosopher Pythagoras — held back composers who longed to explore greater musical complexity.

The adjective that applies to equal temperament is "well-tempered." Bach wrote a set of keyboard pieces, The Well-Tempered Clavier, to show off the advantages of equal temperament. A "clavier" or "clavichord" was any generic keyboard instrument of Bach's time.

This site gives a wonderful introduction to The Well-Tempered Clavier and to J. S. Bach's music in general. I have just begun exploring it, but one thing I can recommend to you right away is that you position your mouse over the "Book II 2. c minor" entry in the scrolling list, then click on it. A little panel appears as the first notes of a fugue are heard. Move the mouse pointer to it and click on "Play movie!" That brings up a Macromedia Shockwave (actually, Macromedia Director) presentation concerning Bach's C-Minor fugue.

In the presentation, at the top you see the measures of the musical score roll by as the corresponding music plays. In the bottom right corner there's a timeline view of the four voices in the fugue, measure for measure. You can click to pause the music, then click again in the timeline to restart it at the clicked measure.

At the lower left is a scrollable narrative description of the fugue. In it are underlined hotlinks that, clicked on, take you to various points in the music. Some of them play the music from that point on to the end of the piece. Others just play a snippet of the music and then stop. These hotlinks help the author of the presentation make numerous key points about Bach's composition.

The timeline is interesting because it highlights crucial aspects of Bach's musical structure, such as how the theme begun in the first measure is restated by a second voice in the following measure, and then by two more voices in subsequent measures (mm. 4 and 7). Then there are reiterations and transformations of this subject or theme in (count 'em) 21 later measures, highlighted in blue on the timeline.

The theme, which lasts but a single measure, is offset by an eighth rest such that it starts after the initiation of any particular measure and laps over into the next measure. You can hear just the basic theme (the version starting in measure 1) by clicking on "subject" in the narrative.

The presentation is the best I have ever seen of a musical piece — I would love to know how to put one like it together myself — and I can hardly wait to examine the other Bach pieces having similar presentations.