260 Chapter 17
tunings. In the more normal setting of a choral rehearsal, he used a piano to give an accu-
rate starting pitch and then allowed a well-trained chorus to sing without any accompani-
ment, in order to observe toward which temperament it naturally tended, the natural or the
tempered tuning. His first experiments used a passage from a sacred motet by the great
composer Heinrich Sch ü tz ( figure 17.2 , ♪ sound example 17.1), a sophisticated choice that
reflects both Planck ’ s knowledge of the repertoire of older masterworks as well as his
ability to choose a telling example.
Sch ü tz ’ s collected works had appeared only a few years before, part of a new wave of
interest in long-forgotten works that involved such serious musicians as Brahms and
Philipp Spitta, and clearly also Planck. The passage he chooses is an exquisite example
of Sch ü tz ’ s word-painting, setting long, lulling notes to the word ruhe , signifying the
repose of the believer who is awaiting resurrection, using the minor subdominant at that
point to achieve an effect at once moving and unearthly.^18 Planck attended many rehearsals
of this work by the chorus of the Royal Musical Hochschule in Berlin, a highly trained
ensemble. He noticed that, if the piano accompaniment were too soft to be heard, the
chorus would sink in pitch enough that the conductor would then tap his baton, break off,
and repeat the passage with the piano. Planck realized that the sound was not only “ espe-
cially good ” when supported by the tempered piano but that, in fact, though flat in pitch
when unaccompanied, the chorus still moved toward a tempered triad, not the natural one,
as Helmholtz would have expected.Figure 17.2
Planck ’ s test passage from Heinrich Sch ü tz ’ s motet “ So fahr ich hin zu Jesu Christ ” (SWV 379, Geistliche
Chorwerke , 1648). Text: “ Thus I fall asleep and rest soundly ” ( ♪ sound example 17.1).