Nasals usually have an additional formant around 2500 Hz. The liquid [l] usually has an extra formant at 1500 Hz, while the English "r" sound ([ɹ]) is distinguished by virtue of a very low third formant (well below 2000 Hz).
Plosives (and, to some degree, fricatives) modify the placement of formants in the surrounding vowels. Bilabial sounds (such as 'b' and 'p' as in "ball" or "sap") cause a lowering of the formants; velar sounds ('k' and 'g' in English) almost always show f2 and f3 coming together in a 'velar pinch' before the velar and separating from the same 'pinch' as the velar is released; alveolar sounds (English 't' and 'd') cause less systematic changes in neighboring vowel formants, depending partially on exactly which vowel is present. The time-course of these changes in vowel formant frequencies are referred to as 'formant transitions'.
If the fundamental frequency of the underlying vibration is higher than the formant frequency of the system, then the character of the sound imparted by the formant frequencies will be mostly lost. This is most apparent in the example of soprano opera singers, who sing high enough that their vowels become very hard to distinguish.
Control of formants is an essential component of the vocal technique known as overtone singing, in which the performer sings a low fundamental tone, and creates sharp resonances to select upper harmonics, giving the impression of several tones being sung at once.
Spectrograms are used to visualise formants.
|Vowel||IPA||Formant f1||Formant f2|
|u||u||320 Hz||800 Hz|
|o||o||500 Hz||1000 Hz|
|ɑ||ɑ||700 Hz||1150 Hz|
|a||a||1000 Hz||1400 Hz|
|ø||ø||500 Hz||1500 Hz|
|y||y||320 Hz||1650 Hz|
|æ||ɛ||700 Hz||1800 Hz|
|e||e||500 Hz||2300 Hz|
|i||i||320 Hz||2500 Hz|
|Vowel||Main formant region|
|e||400–600 and 2200–2600 Hz|
|i||200–400 and 3000–3500 Hz|
Patent No. 7,756,703 Issued on July 13, Assigned to Samsung Electronics for Formant Tracking Apparatus, Method (Chinese, South Korean Inventors)
Jul 14, 2010; ALEXANDRIA, Va., July 15 -- Yuan Yuan Shi of Beijing, Yongbeom Lee and Jaewon Lee, both of Seoul, South Korea, have developed a...
Formant Transitions in Ataxic Speech: The Shape and Speed of Formant Trajectories in Individuals with Multiple Sclerosis and Control Speakers
Dec 01, 2010; Trying to identify the acoustic bases of reduced intelligibility, investigators have paid special attention to the behavior of...