How to select a stable part of the voice.
Record or Open an /a/ sound and add information about the speaker and recording:
Not all parts of your recording will be useful for analysis. Selecting a part of the recording is done with the buttons around the Select button. If the current interval is smaller than the current window, the boundaries of the current interval are indicated by vertical blue lines. With Zoom in (+) and Zoom out (-) you can decrease and increase the size of the window. With the Previous and Next buttons you can step through the recording. With the Select button you can indicate the start and end of the preferred interval.
Go to the Spectrogram for selecting a stable part of your /a/ recording. Zoom out until you see the complete recording. You might notice that the recorded sound is not 4 seconds long (or whatever your recording setting is). TEVA will cut off silence at the start and end of the recording. A stable /a/ sound will show a smooth spectrogram with many harmonics as horizontal lines. The more harmonics are clearly visible, the better the voice is. Find the longest stretch of speech with many, flat harmonics. This will be the interval to analyse. For the Acoustic Signal Typing analysis, around 1-2 seconds of speech are needed.
Click on Select. A blue text will appear below the display "Select new start time (or press Select or a key to continue)". If you press Select again or press any key on the keyboard, the selection procedure will stop. Use the mouse pointer to click on the start of the desired stable interval inside the display. This procedure can be done much easier by simply clicking on the display at the point where you want the border to be. This will automatically bring you to step two of the Select procedure.
A vertical blue line will be draw at the point where you clicked. The text below the display will have changed to "Select new end time, - or + for a 1 or 2 sec window (cancel with Select or another key)". Use the mouse pointer to click on the end of the desired stable interval inside the display. A second blue line will appear and the text disappears. If you press the - key, a new interval of 1 second wide will appear centered on the point you selected in step 1. If you press the + key, a new interval with a width of 2 seconds will appear.
If you now click on the Play button, you will hear only the fragment you selected. The blue lines will be present in all other displays, except the Ltas display. The Ltas display will have changed and will only give the spectrum of the selected interval. All the statistics printed below the displays will refer to only the selected interval.
You can move around the selected interval with the Previous and Next buttons. You can make the window match the selected interval by clicking on To selection.
© R.J.J.H. van Son, December 20, 2011