Acoustics of
the Vowel
Preliminaries
the Vowel
Preliminaries
Materials Part III - Ambiguous Correspondence between Vowels and Patterns of Relative Spectral Energy Maxima or Formant Patterns or Complete Spectral
Envelopes
M9.3: Ambiguity and Individual Vowels
Content of illustration - Comparisons of sounds of /y, i/ and /ö, e/ for which the ambiguity
of spectral peaks and/or calculated F1–F2
relates to the configuration of the levels of the harmonics, to the
spectrum above F2, and to the levels of calculated formants including F3
Content of illustration
The series in Section M9.1 present ambiguities as discussed here for all combinations of the long German back vowels and /a–ɑ
/ and for all combinations of the long German front vowels. Thus, the ambiguities are not a phenomenon of overlapping F1–F2
spaces of neighbouring vowel qualities but, in most cases, a consequence of the dependence of vowel-specific, relative spectral
energy maxima and lower formants ≤ 1.5 kHz on fundamental frequency, interrelated with an observable variation of higher vowel-related
spectral parts for sounds of front vowels.
However, two restrictions apply.
Concerning the sounds of back vowels and of /a–ɑ / investigated, the demonstration of a possible ambiguity of the lower spectral
envelope and of F1–F2 is unquestionable for comparisons of sounds of /u / and of /o /, and of /o / and of /a–ɑ /. For the
comparison of sounds of /u / and of /a–ɑ /, however, the demonstration of a possible ambiguity is limited to similar calculated
F1–F2, but because of high F0 of the sounds of /u /, this calculation is methodically unsubstantiated. Further direct comparison
of the spectral envelope and the configuration of the levels of the harmonics generally provides no clear indication. Notwithstanding,
it is important to consider the fact that sounds of /u / can be produced at a level of F0 that can corresponds to F1 of sounds
of /a / and that, in such cases, exhibit a dominant first harmonic.
Concerning the sounds of front vowels investigated, the demonstration of a possible ambiguity, which is related to differences in F0 of the sounds compared, does not concern the direct comparisons of sounds of /e, ø /, and of / i, y/. As mentioned, in such cases, the ambiguity relates to the configuration of the levels of the harmonics, to the spectrum above F2 and to the levels of calculated formants including F3. This phenomenon is again illustrated in the following three figures.
Comparisons of sounds of /y, i/ and /ö, e/ for which the ambiguity of spectral peaks and/or calculated F1–F2 relates to the configuration of the levels of the harmonics, to the spectrum above F2, and to the levels of calculated formants including F3
Figure 22: Three sound pairs of /y, i/, each pair produced by single female speakers; related model patterns of spectral peaks
and/or of calculated formant frequencies = 290–2150 Hz, 315–2100 Hz and 350–2100 Hz, respectively.
>> Link to Figure 22
Figure 23: Sounds of /y, i/ produced by different male speakers; related model pattern = 230–2050 Hz.
Figure 24: A sound pair of /ø, e/ produced a single male speaker; related model pattern = 350–1700 Hz