Formant

As formant (from the Latin formare = shape ) is known in acoustics or phonetics, the concentration of acoustic energy in a certain frequency range. Formants arise, for example in the resonance spectra of musical instruments or the human voice. Due to the resonance characteristics of an instrument (or the articulation space ) certain frequencies are amplified relative to other frequency ranges. Formants are those frequency ranges in which the relative gain is the highest.

Notes to the definition

In the larynx, or, for example, in the mouthpiece of a wind instrument, a root with numerous overtones is first produced. Only the sound of a musical instrument or on the road between the larynx and mouth opening another part is out of this range, a part of the harmonics, ie partial or partials or harmonics and noise components, muted, amplified by resonance relative compared to the fundamental frequency and compared with other overtones. The areas at which there is a maximum relative gain, the formants. Voices and instruments frequently have multiple Formantregionen that do not directly connect to each other.

The location and severity of the formants significantly shape the tone color (timbre ) of a musical instrument or voice. Through them, let voices and musical instruments different from each other - as the voices of two women or a violin from another.

The location of the formants depends on:

• In mechanical musical instruments from the design and the materials used, especially the design of the sound
• Is, as he adjusted to the human voice from the shape of the vocal tract to articulate a particular text by muscle movements
• On electronic musical instruments of the band-pass and band-stop filters used.

Language

In human language, the position of the formants characterizes the importance of certain sounds. Based on the first two formants in the vowel triangle or trapezoid in the vocal all vowels of a sound system can be distinguished from each other. The vowel formant differ from person to person, especially between men, women and children. Here is an illustrative table of the averaged formant from the said vowel triangle.

Table 1: Averaged formant of the vowel triangle

The two first formants F1 and F2 are important for the intelligibility of the vowels. Your Location characterizes the spoken vowel, the third and fourth formant f3 and f4 are no longer essential for the understanding of language. They characterize rather the anatomy of the speaker and the articulatory characteristics and the timbre of his voice and vary according to the spokesman. In addition, the character of a voice or by the fundamental frequency 100 to 250 Hz and articulation characteristics is determined. The fundamental frequency is the man at about 130 Hz and with the woman at about 240 Hz

Formants, which lie between 1500 and 2000 Hz, bring forth the effect of the Näseleffekts what is called matter Näselformant. If the velum is open, enter, often two Nasalformanten added. For this there are several studies which have shown different Nasalformanten. The first Nasalformant is specified with values ​​between 200 and 250 Hz, the second Nasalformant very different with values ​​between 1000, 1200, 2000 and 2200 Hz

The analysis of formants plays, among other characteristic aspects of a voice, even a significant role in the speaker recognition in forensics.

Table 2: Typical spectral enhancement ( bottom - up Oktavbreite ) which is used specifically for the audio recording of vocals and instruments.

Special features of the vocal

Basically for singing the same as for the language. The above-mentioned formants can be especially good for low-pitched sounds, such as sung in the show Schnarr register. But already in the higher range of a soprano voice fundamental frequency is above the first formant frequencies listed in Table 1. At frequencies of 700 Hz, for example, therefore, would have the vowels u, e and i be incomprehensible and form only weak, non- viable tones because of the strong attenuation between the formants. However, the formants are not independent of the root by Sundberg. This independent variation of the formants is for example practiced in overtone singing. If the root falls within the range of the first formant or above, then rises with the root note of the first formant. This achieves the singer when she opens her mouth on. This adjustment of the first formant is called Formanttuning. It performs the i, u, e to an increase of the 1st formant, he is at a fundamental frequency of 700 Hz also at about 700 Hz when a he remains largely constant. The second formant other hand, drops in e and i and increases when u The rise of the first formant but is not "infinite" on, in the range of h2 and from there they would do nothing more with further opening of the mouth. The vowels are no longer distinguishable at very high tones, because now the fundamental frequency is always above the first formant and thus the sound impression of this formant disappears.

Frequencies around 3 kHz play a crucial role in the capacity of a voice. That's why we call this frequency range Sängerformant. The Sängerformant is well pronounced when in a broad band 2800-3400 have sung in a tone frequencies a "relative strength", regardless of the root.

History

The term formant was introduced in 1929 by Erich Schumann in his habilitation thesis in Berlin, and created a wide field of research both on analytical, technical news sounded like synthetic domains.