Diplophony
| Classification according to ICD-10 | |
|---|---|
| R49.0 | Dysphonia |
| ICD-10 online (WHO version 2019) | |
Diplophony and biphonation denote a double tone of the vocal sound , so two basic frequencies can be perceived at the same time . Often both terms are used synonymously, but there are also differentiating definitions:
- Biphonation : There are two different sources of sound in the larynx ; another frequency is added to the original frequency that does not have to be octave apart . For example, this can be caused by paralysis of the vocal cords when the glottic gap is open . The vocal folds differ in mass or stiffness, which is why each vocal fold vibrates at its own frequency.
- Diplophony : The successive oscillations of the fundamental frequency alternate with different amplitudes . The actual pitch can therefore only be heard attenuated, instead of this the tone that is an octave lower is perceived, since the oscillation only repeats itself de facto after two periods, which halves the perceived frequency. This can be caused by an isolated amplification of partials in the extension tube , as can also be the case with overtone singing . Diplophony can also be caused by excessive and uneven tension in the vocal folds.
literature
- Tadeus Nawka, Günter Wirth: Voice disorders. Deutscher Ärzte Verlag, Cologne 2007, ISBN 3-7691-1142-7 .
Individual evidence
- ↑ In the Pschyrembel (259th edition) there is only the general definition
- ^ Tadeus Nawka, Günter Wirth: Voice disorders. Page 78, see literature
