Vowels dominate perceived loudness while consonants carry intelligibility

Evidence

The time function of perceived loudness is given on the top curve. It is strongly smoothed, but shows single syllables with relatively clear separation. It becomes clear from this curve that peak loudness, normally assumed to be perceived loudness, is produced by the vowels in speech. Consonants and plosives are very important for understanding, and are clearly visible in the specific loudness versus critical-band rate versus time patterns; their contribution to the total loudness, however, is almost negligible. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1307

It becomes clear from this curve that peak loudness, normally assumed to be perceived loudness, is produced by the vowels in speech. Consonants and plosives are very important for understanding, and are clearly visible in the specific loudness versus critical-band rate versus time patterns; their contribution to the total loudness, however, is almost negligible. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1307

Categorization

• XREF: Relevant to speech intelligibility research and to the ADDENDUM on trees/soundscape themes; also informs audio engineering about why syllabic separation tracks vowels. — connects to: Operators lowering volume to fix loudness harms speech intelligibility — , Toole, Floyd E - Sound reproduction-…, 1359; Percentage of lost consonants maps directly to intelligibility quality thresholds — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2465; Low-frequency transport noise masks the vowels that carry speech meaning (+6 more)
• CANDY: A neat elevator fact: in speech, loudness comes almost entirely from vowels, yet understanding comes from consonants.
• corroborated: 3 independent passages support this claim — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1307

Broader Connections

• Operators lowering volume to fix loudness harms speech intelligibility #exemplifies (0.85) — , Toole, Floyd E - Sound reproduction-…, 1359
• Classical spectral-peak vowel coding is especially vulnerable to noise and level changes #exemplifies (0.85)
• Low-frequency transport noise masks the vowels that carry speech meaning #exemplifies (0.82)
• Percentage of lost consonants maps directly to intelligibility quality thresholds #exemplifies (0.80) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2465
• Slow envelope fluctuations up to 16 Hz predict consonant-in-noise perception. #expands (0.78) — Dijk, Pim van, Physiology, Psychoacoustics and…, 5575