Table 1.
Main acoustic parameters and terms discussed in the current article.
| Acoustic parameter/term | Definition/Description |
|---|---|
| Amplitude | Level of energy in a vocalization. Involves the lungs and trachea. |
| Bandwidth | The difference between the highest and lowest frequency. |
| Duration | The length of a vocalization from start to finish. Involves the lungs and trachea. |
| Formants | Frequencies that correspond to the vocal tract’s resonances. Involves the vocal tract (pharynx, vocal/nasal/oral cavities, lips, and nostrils). |
| Frequency modulation | Variability of the dominant frequency or F0 across the call. |
| Fundamental frequency (F0) | The lowest frequency in a vocalization. Involves the lungs, trachea, and larynx. |
| Phonation | The transformation of air flow into sound by vocal fold oscillation. |
| Spectral noise | Proportion of noise in the vocalization, where the harmonic structure is not clear or cannot be detected. |
| Vocalization | The active generation of sounds by the vocal tract (pharynx, vocal, nasal and oral cavities, lips and nostrils) that express a distinctive inner state, occurring spontaneously or as the result of an external event. |
| Vocalization rate | The number of calls that occur per time unit. |