L541: Introductory Phonetics (Spring 2004)
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WaveSurfer Guide for L541

Part 7: Formant plot

[Index | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10]

Preparation: Use the sound file hw06_boston.wav for your practice. Open the file with the waveform cofiguration. Select and zoom-in the part of "here in Sterling Heights, Michigan". Create a Formant Plot pane.

Formalnt Plot

• Right-click on the waveform.
• Create a Formant Plot.
• Formant values at the cursor are displayed on the bottom of window. Values will be displayed when you move the cursor on the formant plot.

Lock data plot

When you drag the cursor, the tracked formant lines are modified. To avoid this function, you need to lock the data plot.

• Right-click on the formant plot, and select Properties.
• Check the lock data plot option.

Properties of Formants

In order to measure formant values as accurately as possible, you can change several parameters in the Properties of Formants plot (Right-click on the formant plot and select properties).

Parameters of Formants Properties

Number of formants: Use 3 or 2. default = 4.

Analysis window length: Use default value.

Pre-emphasis factor: Use a value between 0 and .99 (Recommended value are between 0.96 and 0.99)

Frame interval: Use default value for vowel analysis.

LPC order: Use values between 8 and 20. In general, use a higher number for male, a smaller number for female.

LPC type: I can't figure out this parameter. Use default value (=0).

In the top figure, pre-emphasis factor was 0.7, LPC order was 12. Below is the formant analysis with pre-emphasis factor =0.96 and LPC order =20. You will see that the formant values are nicely tracked with the new parameter setting.

Save your parameter configuration

If you repeatedly do same analysis of formants, you can save your properties.

• Right-click on the formant plot.
• Select Save Configuration.
• Name your configuration and save it. For example, save as "MyFormant".

Apply your pre-stored parameter configuration

• Open the sound file you want to analyze.
• When you choose the configuration, you will see your saved configuration.
• You can apply your customized configuration even after you opened the file with a different configuration by selecting "Apply Configuration ... ".

Spectrum analysis

Formant plot requires computation of the whole sound. Spectrum analysis is a quick way to check the formant values for a specific point or a selected portion. Peak values in the Spectrum Section Plot corresponds to formant values.

• Right-click at the point you want to measure formants.
• Select Analysis and Spectrum Section.
• Select LPC Analysis.
• Change the Order if needed.

Tips for Formant Measurements

• Measure in the middle of the vowel to reduce the contextual effects.
• Change the LPC order if needed.