Saturday, November 30, 2019

The Pitches of the Music for NPR's All Things Considered Are (Just About) Right on Time

This post combines the music I considered in my post of two years ago with the methodology of my post here about some of Carl Vine's music and here about some of Sergei Prokofiev's music that show correlations between the pitches and tempos of a musical work.

Below is a partial transcription of the middle of the theme music for NPR's All Things Considered. During this middle, the music transitions from 4/4 to 5/8 with the eighth note as a common pulse. At this point of transition, there is also something of an authentic cadence in B major: a top-voice A#5 harmonized by a F-sharp-major dominant triad resolves to a top-voice B5 harmonized by what will probably heard as a B rooted chord, even though an E replaces the expected D# -- making a 027 -- and the F# is in the bass. In the 5/8 section, the change of bass from this F# to C and back again occurs every three measures.


Into the 5/8 section, there is a slight increase in a particular hypermetric frequency: the two-4/4-measures pulse (16 eighth notes long) speeds up just a tad to the bass's three-5/8-measures pulse (15 eighth notes long). When spanning two pitches, this 16:15 ratio is the just diatonic semitone. Indeed, if one transposes this particular 16:15 tempo interval of .4375/.4666... Hz up a few octaves so that it sounds as the pitch interval of a semitone, and moves the two notes up to the next available equal-tempered semitone -- if A4 is 440 Hz -- then this pitch interval is A# to B, the same top-voice melodic motion at this same point of metric transition. Furthermore, the 5/8 downbeats, which come three times as frequently as the .4375 Hz change-of-bass frequency, would correspondingly map onto an F#, which accompanies the B in the 027 harmony at the metric transition. These tempo-pitch relationships are summarized below, using a color coding from above (16:15:5). The two outside three-note groups are pitches in equal temperament, and the middle three-note group expresses the three aforementioned tempos as pitches, using a ten-octave transposition.



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