Broadband spectrogram ( Window Length: 0.005s) is used to observe the formant structure of sound, and it is the default setting in Praat.Wideband spectrogram is used to observe the formant structure while narrowband spectrograms reveal the harmonic structure (pitch information). For the window length around 20-30ms (bandwidth: 30-50Hz), the spectrogram is called 'narrowband'. 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'.

The shorter the window length, the larger its bandwidth (Bandwidth = 1.299 / window length). Praat can provide you with both Broadband spectrogram and Narrowband spectrogram by adjusting the window length. You can adjust the View range by clicking 'Spectrum' → 'Spectrogram Settings' For music, we may need to focus on the area from 100 to 2,000 Hz. 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. View range decides how much of the spectrum is shown. The most important settings here are the window length and view range. Normally the waveform and spectrogram will be presented automatically if you select one file and click 'View and Edit'as Figure 1.50.

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