Open mouth overtones

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I could ask this direct from Rollin or Wolfgang but maybe somebody else is also interrested.

If we filter overtones in mouth by tonque, we get low overtones from large space and high overtones from small mouth. Makes sense, longer waves fit in large space. But when I filter overtones by opening mouth, I get high overtones by opening my mouth wide open and low by closing it. Understand? What is the physical explanation?

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Permalink Reply by Jens Mügge on May 8, 2012 at 1:49pm

What is the physical explanation?

- do you know the answer, Sauli ? I don't know it and hope someone else know it :)

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Permalink Reply by Marco Tonini on May 8, 2012 at 2:56pm

The answer is really simple.
You have to consider the formants theory, by which the differences among vowels is fixed by F1 and F2 (1° and 2° formant) in relation to this image; 

as you can see when you pass from /a/ (opened mouth) to /u/ (closed mouth) F1 and F2 decrease their frequencies because the tongue's movement creates more space on the oral cavity, between the tip of the tongue and lower teeth.

On one cavity technique we can produce overtones linked with F1 (in some cases F2 too), while on two cavity technique the movement of the tip of the tongue touching the palate creates converse volumes between F1 and F2. So if F1 increases, accordingly F2 decreases, and vice-versa.

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Permalink Reply by Marco Tonini on May 8, 2012 at 2:58pm

Hi Jens, I'm going crazy cause my tinnitus...

Jens Mügge said:

What is the physical explanation?

- do you know the answer, Sauli ? I don't know it and hope someone else know it :)

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Permalink Reply by Wolfgang Saus on May 8, 2012 at 3:01pm

You may look at the cave under your tongue as a Helmholtz resonater which rises it's resonance frequency by decreasing it's volume and widening it's opening - and vice versa.
Usually sygyt-like overtones are obtained by a combination of 2nd and 3rd formant. In this case you combine multiple movements, one of which is the lip opening. By closing your lips you lower the 3rd formant and enhance lower overtones. It's better to keep the lips more closed in sygyt styles, though, because otherwise your 1st formant joins in and disturbes. If you sing so calles one-cave-techniques lip opening becomes more important because you then combine 1st and 2nd formant.

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Permalink Reply by Wolfgang Saus on May 8, 2012 at 3:09pm

Hi Marco,
where does this theory with the converse volumes in two-cave-techniques come from? My own investigations show a significant lowering of the 3rd formant when rising the tongue tip to the pallet. Not effect on the first formant.

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Permalink Reply by David Stuetzel on May 8, 2012 at 6:23pm

kind of video respose ;-)

 

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Permalink Reply by Sauli Heikkilä on May 9, 2012 at 9:00pm

Thanks for responding and specially Daniels video, which did not give answer but great ideas. And no, Jens, I am still looking for it. Formant-theory is good, but I have to try it to get full understanding. Thanks again.