does anyone know what the acoustic parameter of phonation is in a sound wave? I mean, how can we recognize if a sound is voiced or voiceless (and devoiced, of course) based on its wave?

I've been searching online but I unfortunately couldn't find a clear-cut answer concerning the representation of phonation in sound waves.

Can anyone help?!

Thank you very much in advance!

  • Are you looking for an existing Praat feature, or are you planning on writing a program that computes based on the waveform?
    – user6726
    Jan 12 '18 at 18:40
  • Hi, well, I thought there may be some acoustic feature that can be mapped with phonation; e.g. in plosives the voice bar is sth you can rely on to recognize voicing. But does that apply to other categories, too? I mean, can you find the voice bar in afftricates, fricatives, liquis etc? Moreover, what other features can be mapped with phonation, voice bar put aside? That's what I wish to know. Jan 12 '18 at 19:09

Voicing is defined as the semi-periodic vibration of the vocal folds. Accordingly, you look to see if there is something that happens repeatedly at a reasonably low but not ridiculously low frequency, e.g. for a given speaker it might be in the range of 80-200 Hz, but higher or a wider range for another. The technique of autocorrelation can be used to detect such repeated patterns (and underlies computation of pitch). The idea of autocorrelation is to look at the shape of a piece of waveform, and find the most similar part that follows it (within an appropriate window). If there is enough of a semi-regular pattern, you have voicing. If you have creaky voice, this method may well not detect the glottal pulses. If you are not looking at fricatives, you can look for visible voicing pulses in the spectrogram.

You can also look at a spectrogram, looking for the "voice bar", which is high amplitude at a low frequency. With voiceless fricatives, you can get high amplitude from the turbulent airflow, but the frequency is up there above 1KHz: high amplitude in the realm of 200 Hz does not come from a noisy (aperiodic) source. The problem with voice bar as a detector is that with stops especially, the amplitude of the glottal pulses can be low enough that it's hard to detect. Also, if you are looking at spectral slices, you have to make sure that the low-frequency amplitude is enough higher than the amplitude at higher frequencies (this is an issue in case you intend some automated voicing detection and don't have ideal recordings).

Ultimately the various acoustic methods have reasonable but not total success, and the only way to determine if the vocal folds are vibrating is physiologically.

  • Thank you very much! I thought it had to be really simple, but it's apparently a challenging task and not that easy to discover! Jan 13 '18 at 6:56

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