Analysis by Key: Another Look at Modulation

CARI SCHACHTER
of modulation and to see how far a greater emphasis on key change can be
incorporated into a monotonal approach like Schenker's. That hearing
modulations belongs to our moment-by-moment experience of tonal music is so
obvious as to need no comment. But a deep and intense hearing of music cannot
be only from a moment-by-moment perspective, and existing conceptions of
modulation have surely not done justice to the piece of music as a 'com-position'
- something put together to form a unity.
The Tonic as Centre
8 " 8
To hear something in a key, we have to be aware of a tonic note, a pitch that
functions as a centre of orientation to which, directly or indirectly, we relate all
the other pitches . The inference of a tonal centre can result from several factors,
singly or in combination. One factor, mentioned by a host of authors including
Schenker, is the presence of a diminished fifth or tritone between 7 and 4,
expressed either simultaneously (as in a V7 chord) or in succession (as in a
progression of IV or II tO v).2 This diminished fifth is indigenous to major and
must be imported into minor to offset that mode's tendency to gravitate to its
third scale ste?, a tebndency produced by minor's own indigenous diminished
fifth between 2 and 6. It is easy to hear how the diminished fifth clinches the
key in b. 3 of the C major Prelude from Bach's WTC I (Ex. 1).
Ex. 1 Bach: WTC I, Prelude I, bs 1-4
+ 11 - 8 8 1
Of course our awareness of the tonic cannot come from a disembodied
diminished fifth; we must hear it in a context that includes other pitches as well.
In the Bach excerpt, all of the notes of the C major scale appear by b.3; in
addition, b. 1 contains the tonic triad. Beginning with tonic harmony, though it
is the norm, is by no means a prerequisite to our immediate feeling for the key.
Chopin's Prelude Op.28, No. 18 sounds unmistakably in F minor at least from
the end of b. 1, though a stable tonic chord does not appear until the very end of
the piece. The dominant ninth, with its tritone Bb-E, locates F as the tonic pitch
(although the only Fs in the citation are passing notes), and the emphasized DS s
suggest - even in the absence of Ab- that this F is going to be minor (Ex. 2).
Tonal music's power to create a sense of future through the specificity of the
. .
expectatlons lt can arouse has no parallel in any other kind of music of which I
am aware; that its signals are at least as often contradicted as they are confirmed
290 MUSIC ANALYSIS 6: 3, 1987
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