Friday, March 21, 2014

Rhythmic Architecture, part 1

First, let me explode two common myths about musical structure. For one, the best way to create harmonies is from the top down. The top line has to be making musical sense, and this doesn't result often enough when "stacking" harmonies from the bottom. Another common concept that needs revising: thinking of rhythm from the bass up. To understand rhythmic structure, start at the fastest pulse and let different instruments express substructures and accents at lower levels. Many genres of music are defined by assigning separate levels of rhythm to various instruments. John Meheghan's second book, Jazz Rhythm and the Improvised Line  illustrates this well, and The Rhythmic Structure of Music by Grosvenor Cooper and Leonard Meyer has a broader, more scholarly focus on the "architectonic levels" of music.

In brief, one may employ duple or triplet rhythm as the most basic building blocks. Walking and marching beats are duple. Gliding and twirling motions are associated with the waltz, the original forbidden dance because of the intoxicating abandon that characterized its performance. Things get really interesting when we allow the spirit of African rhythm into our performance. The use of polyrhythms (more than one rhythm at the same time), especially two against three, greatly enriches the listening and dancing experience!

American musical history involves the weaving of many threads. In the days of the sailing ships, pulling up stakes and heading for the "new world" must have been like going to Mars would be for us today. The many cultures that contribute to our 21st century sensibility were originally kept intact for hundreds of years in the enclaves of immigrants and slaves. The homogenizing tendency of recorded music arrived in full impact around the start of the 20th century, blending folk and traditional elements in song form, harmony and rhythm. Early popular music of the two-beat variety gained energy from tempo and associated dance styles, and New Orleans ragtime and jazz began to infuse the culture with syncopation. The most basic syncopated rhythm is the quarternote - halfnote - quarternote pattern in 4/4 time. With the introduction of a strong beat on 2 and 4, the American "backbeat" was born.

Soon enough the boogie woogie pattern was sparking the dancers. Pretty much straight eighth notes, the major chord was spelled out with two eighths on 1, 3 and 5 for the first 3 beats of a measure in 4/4 followed by some variation on the last two eighths, often simply 6-5. Variations on the boogie pattern abound, providing impetus to composers in many genres which transcend the early stylistic requirements of boogie woogie and associated "barrelhouse" piano styles.

The advent of swing in the 1930s smoothed the stiff pairs of eighths into a triplet rhythm. Instead of a rigid 8 to the bar pulse, there was an implied pulse of 12 beats, with 8 notes sounded. Notation posed a problem -- triplets are written with the next smaller note division as a group of three. Now each quarter note (previously subdivided into two eighths) would have to be notated as either two eighths tied together followed by another eighth (with a bracket and the number 3 enclosing the group) or as a series of quarter-eighth groupings (again bracketed with a 3). Eventually the implied 3 eighths against the old 2 were spelled out as a dotted eighth followed by a sixteenth, the connecting bar solved the grouping problem (no unwieldy 3s cluttering the sheet music), and it was understood by convention that the dotted eighth and sixteenth pattern was to be "swung."

Next installment of this 3 part series on rhythmic architecture will be a study of early R&B, early rock, and the apotheosis of funk!

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