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the harmonics above 4,000hz are well-practiced performer holding a symbols derived from the spectral
sharply attenuated in the Narrow drone, this technique may be used envelopes of the four timbres dis-
Band timbre, putting the main focus to create whistle-like melodies that cussed previously that can be used
on the 2nd, 3rd, and 4th harmonics. follow the pattern of the overtone by conductors interested in a quick
I believe this narrow harmonic fo- series. In a vocal ensemble, the pedagogical reference to indicate
cus is what allows Bulgarian choirs technique can be used as a gener- which timbres they are interested
to maintain timbral homophony ally brighter timbral eff ect or to in hearing from their ensemble, or
(choral blend). Like the Fundamen- acoustically recreate an electronic for those who may find it helpful to

tal Dominant sound, timbral ho- “fi lter sweep” by moving between understand these symbols as they
mophony among voices singing the high and low harmonics through encounter them in contemporary
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same melodic line is partly achieved various vowel shapes. This extreme literature. Again, the four timbres
by having all singers emphasize the narrowing of the vocal tract can be are:
same harmonics. In a vocal ensem- achieved initially through use of a
ble setting, this is typically achieved retrofl ex American ‘R’ [ɹ] shape, • Fundamental dominant with at-
by asking singers to match the same with the back and sides of the tenuated upper harmonics (Funda-
shading of vowel, since each vowel tongue very high. mental Dominant sound)
boosts its own set of frequencies (as Reinforced harmonics can also
illustrated in Image 3). If that em- benefi t from a touch of nasality in • Wide spectrum of emphasized
phasis boosts only a small range of the sound. The specifi c overtone harmonics (Wide Spectrum)
harmonics, like in the Narrow Band emphasized can then be adjusted
sound or the Fundamental Dom- through very small changes in lip
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inant sound, then it will be easier and mouth shape (Image 6).
to achieve a greater degree of tim-
bral homophony. Because the Wide
Spectrum boosts harmonics over an Visual Representation of
extensive range of frequencies, it will Timbral Categories
more readily create timbral hetero- Because of the relatively consis-

phony (the effect of many individu- tent spectral envelope of each tim-
als singing at once). 14 bre, I will propose a standard set of

Individual Upper Harmonics
Dominant with
Attenuated Fundamental
(Overtone Dominant)
Much like Narrow Band sing-
ing, the Overtone Dominant timbre
boosts a small band of frequencies
while suppressing the fundamental
pitch. By contrast with the Narrow
Band sound, Overtone Dominant
singing narrows the boosted band Image 6. An MRI image of Anna-Maria Hefele overtone singing and the corresponding
of frequencies to the point where spectral envelope. Note the narrowing of the vocal tract with the high placement of the
only one harmonic at a time is em- tongue and in the throat in the upper image. The spectrograph image ranges from 200hz -
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phasized. When executed by a 10,000hz, with the harmonic boost occurring around 2,000hz.

58 CHORAL JOURNAL April 2021 Volume 61 Number 9