Until now we have only presented the calculation of acoustic features within ‘units’ of our frequency analysis, i.e. within 10ms time-windows. However, it is often desired to examine the
distribution of features across time-windows, so as to characterize natural sound units, such as notes, syllables, motifs and bouts.
Manual segmentation: Open ‘example 2.wave’ and choose
(bottom right of the screen). Then click at the beginning of a syllable. Point to the end of the syllable and click again. The red and blue vertical lines now outline the syllable. The feature distribution of this syllable is now summarized in the ‘features across interval’ window. Now say that you want to save this information about the syllable features.
SA+ saves all information into MySQL tables. To set a new table for your data click ‘new table’ and call it myData. Click on the text box below and type ‘syllable 1’ and then click ‘add record’.
Note that there is now 1 record in myData. Let’s say that you want to save the features of all the syllables of this song. Type ‘all syllables’ in the text box, and click ‘Add record’. The feature distribution summary of these syllables is now saved in our database. You will see how to access this information in a moment.
Automatic segmentation and saving of multiple syllables: Open ‘example 2.wave’ and check
Take a look at the ‘records in table’ label (under ‘data management’), and remember the number of syllables shown. Now outline the entire song by clicking once to eliminate the previous outlining, and then click in the beginning and in the end of the song. Note that there are now 5 additional records in the table although you did not click ‘add record’. This is because all 5 syllables were added at once with their appropriate feature distribution when you outlined the song.
Auto-gegment a single syllable: Auto-outline is a method of automatically (and accurately) outlining the boundaries of a single syllable.
Select
and click twice in the middle of a syllable. The first click will outline the beginning and the second the end of this syllable according to its boundaries, as determined by the amplitude and entropy thresholds. <
Adjusting the average pitch estimate: Calculation of mean and variance values is trivial, except for pitch, where you can choose between simple average or (look at the ‘Settings & options’) tab
method. Adjusting pitch by its goodness can improve the stability of the estimated pitch average. As shown below, pitch values sometime ‘jump’ as a consequence of the method of pitch estimate, which dynamically flips between harmonic pitch and mean-frequency methods. The undesired effect of an unstable pitch estimate can be reduced by adjusting the pitch average by its goodness, so that pitch estimates are endowed with a higher weight when the goodness of pitch is higher. Using this approach in the example below, we obtain an average pitch estimate of 731Hz, only 44Hz higher than the real harmonic pitch, whereas the simple average increases the error seven-fold to 315Hz.