{"id":1147,"date":"2020-03-23T02:10:05","date_gmt":"2020-03-23T02:10:05","guid":{"rendered":"https:\/\/corpus.eduhk.hk\/english_pronunciation\/?page_id=1147"},"modified":"2020-03-31T07:48:56","modified_gmt":"2020-03-31T07:48:56","slug":"1-4-analysis-of-speech-in-praat","status":"publish","type":"page","link":"https:\/\/corpus.eduhk.hk\/english_pronunciation\/index.php\/1-4-analysis-of-speech-in-praat\/","title":{"rendered":"1.4. Analysis of Speech in Praat"},"content":{"rendered":"
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Before using Praat to do sound analysis, we have to be clear about know that what information we can get from Praat. Table 1 presents some major acoustic variables we usually use to analyze the speech sounds. (See Figure 1. 49) for visual presentation of the variables.<\/p>\n

Figure 1.49<\/em><\/strong><\/p>\n

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Table 1.1<\/span><\/i><\/b><\/p>\n

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1.4.1. Extracting sound<\/b><\/p>\n<\/div>\n<\/div><\/div><\/div>

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If you want to extract a section of a sound (usually a single word or vowel) into a different Sound object\u00a0for analysis, you can<\/p>\n

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  1. Select the section of sound by cursor<\/li>\n
  2. Click File \u2192 Extract Selected Sound (preserve times)<\/span><\/li>\n<\/ol>\n

    By doing this, a new sound file will be is created in the Objects window, containing just the selected part of the original sound.<\/p>\n<\/div>\n<\/div><\/div><\/div>

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    1.4.2. Spectrogram<\/span><\/b><\/p>\n<\/div>\n<\/div><\/div><\/div>

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    A. Showing the Spectrogram<\/span><\/strong><\/p>\n

    Normally the waveform and spectrogram will be presented automatically if you select one file and click \"View and Edit\"as Figure 1.50.<\/p>\n

    Figure 1.50<\/span><\/i><\/b><\/p>\n

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    B. Adjusting the Spectrogram Settings<\/span><\/strong><\/span><\/p>\n

    The most important settings here are the\u00a0window length<\/strong><\/span>\u00a0and\u00a0view range<\/strong><\/span>.<\/p>\n

    1) View range (Hz)<\/u><\/em><\/span><\/p>\n

    View range decides how much of the spectrum is shown. For speech, we normally set the range from 0 to 5,000 or 6,000 Hz, but for examining fricatives, we might need to set it as high as 15,000 Hz. For music, we may need to focus on the area from 100 to 2,000 Hz. (Revised from Styler, 2012)<\/p>\n

    You can adjust the\u00a0View range<\/strong><\/span> by clicking \"Spectrum\" \u2192 \"Spectrogram Settings\"<\/span><\/p>\n

    Figure 1.51<\/em><\/strong>\"\"<\/a><\/p>\n

    b)\u00a0Window length<\/span><\/span><\/span><\/em><\/p>\n

    Praat can provide you with both Broadband spectrogram and Narrowband spectrogram by adjusting the window length. The shorter the window length, the larger its bandwidth (Bandwidth = 1.299 \/ window length). There is no clear cut boundary between Broadband spectrograms and Narrowband spectrograms, if the window length is around 3-5 ms (bandwidth: 200-300Hz), the resulting spectrogram is called \"wideband\". For the window length around 20-30ms (bandwidth: 30-50Hz), the spectrogram is called \"narrowband\". Wideband spectrogram is used to observe the formant structure while narrowband spectrograms reveal the harmonic structure (pitch information).<\/p>\n