Part 4: Analysis
Now that you obtained the voice recordings, you are ready to begin the formal acoustic analysis to obtain a variety of speech and non-speech acoustic voice measures. Step-by-step instructions are outlined below, with an 18-minute video tutorial available for viewing.
Non-Speech Acoustic Voice Measures
Mean Habitual F0, jitter (local; %), shimmer (local; %), HNR (dB)
Select the middle 2-3 seconds of the sustained /a/ from the CAPE-V - avoid the onset and offset of the /a/.
Select ‘Pulses’ > ‘Voice report’.
In the voice report window, locate Median pitch (used for Mean Habitual F0), Jitter (local; %), shimmer (local; %), and Mean harmonics-to-noise ratio (dB).
Input these values into your evaluation report.
Exit the voice report window.
Mean Habitual SPL (dB)
The mean dB of the sustained /a/ will be displayed in green (make sure it is highlighted). Alternatively, go to ‘Intensity’ > ‘Get intensity’.
Input the mean habitual intensity into the evaluation report.
smoothed Cepstral Peak Prominence (CPPS)
Using the same 2-3 second selecting of the sustained /a/, select ‘File’ > ‘Extract selected sound (time from 0)'.
Exit out the waveform/spectrogram window so that you are at the Praat Objects window.
A new untitled object will appear in the Praat Objects window which contains the portion of the /a/ you had previously selected. Rename this object to ‘sv’.
Select the ‘sv’ object, then select ‘Analyse periodicity’ and ‘To PowerCepstrogram’. Select ‘OK’.
A new object will appear in the Praat Objects window named ‘PowerCepstrogram sv’. Highlight this file, then select ‘Query – ’ and then select ‘Get CPPS…’ . In the window the pops up, change settings (see video), then select ‘OK’.
The window that gets generated is the CPP. Enter this into the evaluation report.
Minimum F0, maximum F0, and F0 range
'View & Edit' the audio file containing all the voicing tasks.
Click on ‘Pitch’ and ‘Pitch settings’, and temporarily change the maximum pitch to 1300. Click ‘Apply’ and ‘OK’
Zoom in on the approximate location of the maximum and minimum pitch glide tasks.
Highlight the middle 0.5-1.0 second of the highest and, separately, the lowest F0. If F0 was not sustained for 2 seconds, or if there is noise artifact, then manually identify the highest and lower F0 by clicking the cursor on the part of the blue contour that represents the highest/lowest F0. Input values into the evaluation report.
Change the F0 settings back so that the maximum F0 is 800. Then click ‘Apply’ and ‘OK’.
Use an online conversion tool (e.g., http://www.homepages.ucl.ac.uk/~sslyjjt/speech/semitone.html) to determine the number of semitones between the minimum and maximum F0 to get the pitch range. Input this into the evaluation report.
Minimum SPL (dB), maximum SPL (dB), and SPL range (dB)
Zoom in on the location of the minimum and maximum /a/ loudness tasks
Repeat what you did for the minimum and maximum pitch for the minimum and maximum loudness.
To determine SPL range, subtract minimum loudness from maximum loudness, then input into the evaluation report.
Acoustic Analysis: Continuous Speech Voice Measures
Mean SPL (dB), Mean F0, F0 SD, CPPS
Highlight and zoom in on the connected speech sample of the main audio file (e.g., The Rainbow Passage)
Record the mean dB, seen on the right in neon green (or by selecting ‘Intensity’ > ‘Get Intensity’)
Select ‘Pulses’ > ‘Voice Report’. In the Pitch section of voice report, report the Median pitch for “Mean F0” and the Standard Deviation for the F0SD.
Select ‘File’ > ‘Extract selected sound (time from 0). Then exit out the waveform/spectrogram window. A new untitled object will appear in the Praat Objects window which contains the connected speech you had previously selected. Rename this object to ‘cs’.
Obtain the connected speech CPPS by repeating the same steps as was done for the sustained vowel CPPS.
Acoustic Analysis: Acoustic Voice Quality Index (AVQI)
Download the AVQI script: https://drive.google.com/file/d/1G0xU0MN7vfjfLIFhPO_77bCPQhzeIkB_/view
Ensure the ‘sv’ and ‘cs’ files are still listed in the Praat Objects window.
Click ‘Praat’ and then ‘New Praat script’.
Open the AVQI script you just downloaded, then copy and paste the text from that file that was just downloaded into the ‘New Praat Script’ window
Then click ‘Run’ > ‘Run’ > ‘OK’. Wait 1-2 minutes and the AVQI will be generated.
Maximum Phonation Time, S/Z ratio, Laryngeal Diadochokinesis
If you completed maximum phonation time and S/Z ratio, then consider using Praat to measure the total duration of each task and calculating the measures accordingly. Just highlight the duration of each task and look at the duration indicators at the bottom of the spectrogram window.
If you completed laryngeal diadochokinesis, then consider using the sound waveform and the spectrogram with the pitch/intensity contours to quickly count the number of repetitions and divide by the selected duration (e.g., middle 3 seconds).