Formant Tracking Charts

As my teaching schedule becomes more active and the level of my studies become more advanced the posts take more time to produce. It is for that reason that I open the blog to any of you who have an issue relevant to the advancement of our art form to bring it up here in any language that I can review. So don’t be shy.

I have been working on these formant tracking charts for about three years and feel that I have finally gotten enough information to complete them. I am sure that some of you will have commentary and suggestions for improvements. Feel free!

The charts take into account the obvious on the one hand (i.e. plotting harmonic frequencies vs vowel formant frequencies), and the less common (i.e. consideration of vocal tract reactance in chosing the vowel appropriate for a given harmonic). Remember that the formant values represent the formant centers and that there are many vowel qualities between the ones I have chosen to represent on the charts. Following the principles we exposed here in my exchanges with Martin Berggren, formant frequencies are plotted within 50Hz above the relevant harmonic. In the case of an exact match of the formant with the harmonic (or a few Hertz difference), the formant is considered inertial instead of neutral when we consider that the vowel can be subtly modified to bring the formant above the harmonic.

For those who are new to the concept of vowel modification, a couple of things will be obvious: 1) The lower the fundamental frequency the more choice of vowels there are. Therefore male voices have more vowels choices because of the octave differential from female voices. For that reason, all things equal a male singer (particularly a baritone or a bass) will be more intelligible than a female counterpart. 2) In the Excel charts, the cells of F2 (second formant) frequencies are filled with a dotted pattern while those of F1 frequencies are kept clear. The colors correspond to the the colors associated with the vowels on the chart to the right of the grid. 3) The words are from four common operatic languages: English, French, German and Italian and are as follows:

/u/ susurro (Italian)
/U/ Duft (German)
/o/ chose (French)
/O/ tortora (Italian)
/ʌ/ up (English)
/α / father (English
/a/ voila (French)

/i/ midi (French)
/y/ fühl (German)
/Y/ Stück (German)
/I/ fit (English)
/ø/ feu (French)
/e/ été (French)
/oe/ coeur (French)
/E/ met (English)
/ae/ cat (English)

In some cases there is a good bit of distance between one vowel formant and the adjacent one. In the case of /ae/ to /E/ an extra frequency is placed as an intermediary marker. Although they are close in quality the vowels /i/, /y/ and /I/ cover a wide frequency range in the second formant area. Therefore, I take some liberties with the intermediary frequency range in pink.

More will be written about these charts in the coming weeks. However, I could not wait to make them available since I’ve been promising them for the past several months.

Finally, it should be said that these charts were done to improve upon the seminal work done on formant tracking by Berton Coffin. Coffin’s chart did not take F2 frequencies into account for one. Furthermore, vocal tract reactance was not common knowledge during Coffin’s time. As always, the posts are meant to generate discussion so that we may arrive at useful information.

Files are found here in PDF format:

Tongue and mixed Vowels

Lip Vowels

© 11/20/2008