Thursday, October 1, 2015

Another Match in Reich's The Desert Music

This is the beginning of the third year of this blog. To celebrate, I am combining the idea from the first post of two years ago – relating pitch and time – with music by a composer featured in the post from one year ago – Steve Reich. A repeating five-chord progression occurs in the first and last movements of the five-movement The Desert Music. These chords are indicated below. In the first movement, the progression starts with the chord in the upper right and loops clockwise several times. The chord with the D in the bass sounds like a jazzy tonic harmony, whereas the next chord with the A in the bass sounds like a jazzy dominant harmony. In the first movement, adjacent chords after a while begin to overlap with and blur into one another. (This overlap is more conspicuous in the Michael Tilson Thomas recording than in, for example, the Kristjan Järvi recording.)

The ten circles outside the five chords use a circular piano keyboard to indicate notes irrespective of octave and diatonic spelling: C is at the top of each circular piano keyboard. The five circles next to the five chords simply translate the chords into this circular keyboard notation. The other five circles – the ones with arrows pointing toward them – show the union of two adjacent chords. The color coding – with reference to my blog post from a year ago – shows that the union of the dominant and tonic harmonies perfectly matches Reich’s characteristic rhythm, with the note C corresponding with the downbeat.

Furthermore, my Pythagorean slant of a year ago works on the pitch side: the union of Reich’s dominant and tonic chords is the smallest kind of note group that contains an augmented triad, a fully-diminished seventh chord, and a Guidonean hexachord (a major scale without ^4 or ^7). Moreover, the tonic chord is the constituent Guidonean hexachord (the blue star: in fifths, F-C-G-D-A-E), while the dominant chord contains both the constituent augmented triad (the red triangle: A-C#-F) and fully-diminished seventh chord (the purple square: C#-E-G-Bb), and both chords are the usual dominant-functioning harmonies of their respective chord qualities (V+ and vii°7) of the D tonic. In other words, if you trace the red, purple, or blue line in the figure above, you will put the colored dots in the same order that they are on the side of the right triangle from the October 2014 figure of length 3, 4, or 5, respectively: that is, green-red-red-..., green-purple-orange-purple-..., and purple-red-blue-orange-blue-red, respectively.

Saturday, September 26, 2015

I Got Rhythm and Pitch to Match

Today George Gershwin would have been 117 years old. (Imagine what other music he might have written if he had lived to even half that age. He didn’t even make it to a third of that number.)
I suspect the average person familiar with Western music, conceived rather broadly, knows just as well the four notes that follow these

as the four notes that follow these

What makes "I Got Rhythm" so catchy? There’s the pentatonic aspect of the opening pitch materials, which makes the tune quite user-friendly. And there’s the consistent dotted-quarter pulse overlaid on a common 4/4 meter, which makes the rhythm distinctive but uniform nonetheless. These features of pitch and duration have surely already been pointed out. However, what perhaps has not been pointed out is how the pitch and rhythm of the first four notes correspond in a significant way.

Rather than report this correspondence with a lot of words, I will use a couple of pictures, and let the reader figure it out.

This kind of match is rather rare among four-note motives. (Well, in full disclosure, it does happen with I Got Rhythm’s next four notes, but that’s just because they are the same thing backwards.) I will leave it as an exercise to the reader to discover how elements of these images (such as the stack of fourths, and the a-b-a rhythm) infiltrate the composer’s Variations on “I Got Rhythm.” I will leave it as an additional exercise for the reader to come up with a five-note motive with the same property. I can think of one from rock music.

Tuesday, August 11, 2015

More Mirrors: Mussorgsky Matches Mozart

This month last year, pianist Andrej Hoteev and singer Elena Pankratova released a recording of Mussorgsky’s Pictures at an Exhibition and Songs and Dances of Death, informed by original manuscripts. This recording brought Pictures and its various interpretations back into my forethoughts. The late professor of piano Nancy Bricard also consulted original manuscripts in her 2002 edition of Pictures. In her foreword to her edition, she claims that the composer “did not use the sonata form.” While this may be true, the opening of the last movement titled “The Great Gate of Kiev” resembles a sonata without development:

mm. 1-29 Loud heraldic first theme in main key
mm. 30-46 Soft hymnic second theme in a subordinate key

mm. 47-63 First theme again in main key
mm. 64-78 Second theme again, but transposed into the main key

(Hoteev even recommends, in his liner notes, inserting a brief silence before the start of the second theme, which is common at this juncture in traditional sonata forms.) However, the subordinate key is not the key a perfect fifth above the movement’s main key of E-flat, but the key of a perfect fifth below. This inversion of usual tonal practice extends beyond key choice, as the example below suggests. This example lines up a reduction of the exposition and recapitulation of a typical sonata-form movement—I chose the first movement of Mozart’s Eine kleine Nachtmusik—with a reduction of the beginning of “The Great Gate of Kiev.” Whole notes represent roots of chords. T, S, and D refer to tonic, subdominant, and dominant. I chose clefs that made the mirroring between the two movements visually apparent. The subscripted p refers to the “parallel” transformation in German-language music theory, which allows for a change of chordal root without change of function, as I have further shown with the baritone clef, the F clef in the middle of the staff.
[click image to enlarge]

Notice how authentic motions (D-T) in Mozart match plagal motions (S-T) in Mussorgsky, and how each second theme in its respective exposition reaches an apogee—in the thirty-ninth measure of each!—four perfect fifths away from the main key’s tonic, then gradually eases back toward this tonic in the measures that follow.

Wednesday, July 1, 2015

Mirrored Rhyming in "The Star-Spangled Banner"

I have used this blog to make little musical observations and even little musical predictions. This month I will use it to make a little suggestion. This is the month when those in the United States celebrate their independence from the United Kingdom; hence, the “Star-Spangled Banner,” the national anthem of the United States, gets a little more airtime in July than in other months.

There are countless arrangements of this anthem. The music to the left is not in four-part harmony, but is rather the superimposition of melody-bass arrangements of two snippets of this anthem: the music in blue is near the beginning, and the music in red is near the end. Both melodic snippets are from the original tune, and the blue bass line is by far the most common choice for arrangers, although not all, like here. The red bass line, while less common in arrangements, can still be found, like here. This red bass line, when matched with the other notes of my example, produces a neat symmetry if you like that sort of thing: the counterpoint of the two blue lines perfectly reflect around a mirror to produce the counterpoint of the two red lines. When the anthem is in B-flat major—a frequently selected option—this mirror can be placed at middle C, and the treble and bass clefs of the grand staff can well display this symmetry. This symmetry engages not only meter (weak-weak-strong) and relative duration (short-short-long), but also the only internal rhyme (“see,” “free”) in the anthem’s first and, for many, only stanza.

Monday, June 1, 2015

Twisted Tristan

Speaking of anniversaries in multiples of fifteen, Richard Wagner’s Tristan und Isolde premiered 150 years ago this month. Wagner in general, and the introduction to this opera in particular, is well known for withholding the tonic note or tonic triad of a key whose presence is made clear. A very efficient way of doing the former—with two voices, three pitch classes, and three total semitones of voice-leading work—is the progression F3D4 to E3E4 (call it what you want), which is in A although no A sounds. (The C clef, while not as user-friendly for some as other clefs are, will be useful later.) Now take this progression, and skew it by displacing the top voice forward in time. This puts the D above the E, and excludes a D above the F.

Now fill out this twisted progression in four parts, while maintaining some implication of an A tonality. An E7 is the best way to harmonize the second moment. As for the first chord, exactly two of the twelve half-diminished seventh chords have an F and also do not have a D; they are shown below. (My unusual spelling of each half-diminished (hd) chord matches Wagner’s.)

These are exactly the two solutions, allowing for transposition (shown using the roving clef below), used in the famous opening eleven measures of the opera's instrumental introduction: Wagner’s first two progressions use the first solution, and his third progression uses the second solution.

Moreover, both chords contain a note—either C# or D#—that is only a half step away from the D: a clear “not-D” note through its half-step displacement. Lastly, this derivation from a two-voice model also jibes well with the voice leading: the voices with the F or the “not-D” note in the first chord (the solid noteheads) each move by a single half step into the second chord, while the two added voices (the hollow noteheads) do not.

Monday, May 11, 2015

Rare Sibling Harmony at the End of Holst’s Solar System

Let us say that a three-note chord’s sibling is a transposition or inversion of the chord; that is, siblings have the same three intervals between their three pairs of notes, allowing for change of octave. For example, F-A-C and C-Eb-G are in the same family—each contains a minor third, major third, and perfect fourth—but C-E-F is in a different family. There are twelve three-note-chord families. Let us further say that the relationship between two (non-identical) siblings in the same family is harmonious if there is no half step, allowing for change of octave, that exists between a note in one chord and a note in the other.

The family of major and minor triads has been shown to be special for many reasons. Here is one more: of the twelve three-note-chord families, the percentage of harmonious types of sibling relationship among the family of major and minor triads is, perhaps surprisingly, the smallest. (In truth, it is tied with the family to which C-E-F belongs.) Shown below are the twenty-three possible types of relationship a major triad can have with its siblings, up to transposition and inversion. The top system shows all eleven non-zero transpositions, the second system shows six inversions around C, and the third system shows six inversions around C/C#. A notehead is filled in if its pitch forms a half step, allowing for change of octave, with a note in the other chord in the same measure: the two clashing notes have the same notehead shape.

Only two out of these twenty-three relationship-types are harmonious: they are the measures without any filled-in noteheads. If you combine together the two triads in each pair into a richer harmony—an F9 chord, and a C#m7 (or EMadd6)—you have the last two chords of Gustav Holst’s The Planets. These are the chords, sung by an offstage female chorus, that alternate with one other until they fade out to silence, that is, unless Colin Matthews’s Pluto, the Renewer follows on their heels, a piece that premiered fifteen years ago today. Pluto also ends with the same choir singing essentially the same C#m7 chord.

Tuesday, April 7, 2015

Verdi Under the Radar

The innovative-chromatic-harmony radar that musicians bring to their hearing of nineteenth-century opera tends to ping more often with the music of Wagner than of that of his contemporary Verdi. However, I like to think of some of Verdi’s innovations as more stealthy than showy.

Take this cadence-ending treble line.

It’s not too hard to imagine this bass line, with an implied Neapolitan chord, underneath it.

Now take this cadence-ending bass line.

It’s not too hard to imagine this treble line, with an implied secondary dominant, above it.

By themselves, these lines imply staples of chromatic harmony. But toward the end of a chorus from La forza del destino ("Nella guerra, è la follia"), Verdi puts them together.

On the one hand, Verdi puts a root-position G-major chord in C-sharp minor music: ping! On the other hand, the stylistically normal soprano and bass lines -- enharmonics aside -- fly right by, sotto il radar. Viva Verdi indeed.