Why Do Folds Separate As We Ascend?

[Matt]

Extending range being one of the hottest topics among singers, and what with all the quack like a duck exercises etc, isnt a major problem for most of us simply that as we siren up higher, our vocal folds begin to slip apart, and the higher and more difficult it gets, the more they're parting? Hence we begin muscling, instead of perhaps adding a little squeak or quack when it begins to get too high to keep closure without beginning to panic and muscle our way up there or since the folds have separated, going over to airy falsetto. But why do the folds begin to separate as we ascend?

[Snax]

I just posted a reply in another thread about babies and how it is that their natural ability to scream and cry loudly for extended periods of time doesn't seem to wear out their little voices. Over time we seem to unlearn our bodies natural tendency to protect itself from things that harm it. A baby doesn't think about wether or not it sounds funny or how irritating its tone is, it just does what comes naturally and lets rip with a nasty pharyngeal shriek that pierces the air and can be hear for miles!

[Steven Fraser]

Extending range being one of the hottest topics among singers, and what with all the quack like a duck exercises etc, isnt a major problem for most of us simply that as we siren up higher, our vocal folds begin to slip apart, and the higher and more difficult it gets, the more they're parting? Hence we begin muscling, instead of perhaps adding a little squeak or quack when it begins to get too high to keep closure without beginning to panic and muscle our way up there or since the folds have separated, going over to airy falsetto. But why do the folds begin to separate as we ascend?

Matt: It has to do with the changing thickness of the vocal bands as a function of the amount of stretch - i.e, the range of the note. Here are the details.

The general pitch-control mechanism of the voice is a trade-off between the muscle action of the Thyro-arytenoids within the vocal bands, which when flexing shorten and thicken the bands lowering the vocal pitch, and the Crico-thyroid muscles which thin and stretch the bands, raising the vocal pitch.

This interaction means that the vocal-band cross section changes over the range. On the lower end, the vocal bands are thicker than they are in the higher end.

Why does this matter? Because this variation in thickness affects the amount of adduction required to bring the vocal bands to the right amount of closure to maintain the consistency of the glottal wave motion. If this wave motion changes, this produces audible changes in tone quality in the voice.

[VideoHere]

The general pitch-control mechanism of the voice is a trade-off between the muscle action of the Thyro-arytenoids within the vocal bands, which when flexing shorten and thicken the bands lowering the vocal pitch, and the Crico-thyroid muscles which thin and stretch the bands, raising the vocal pitch.

This interaction means that the vocal-band cross section changes over the range. On the lower end, the vocal bands are thicker than they are in the higher end.

Why does this matter? Because this variation in thickness affects the amount of adduction required to bring the vocal bands to the right amount of closure to maintain the consistency of the glottal wave motion. If this wave motion changes, this produces audible changes in tone quality in the voice.

steve, with that said if one needs to hold on to the adduction process as one ascends in scale to keep the folds together longer and tighter, wouldn't it help us to have extra development in the muscles that assist with that?

[Matt]

I really dont think so, because while Ive been experimenting with this minor 'revelation' recently, where I can actually feel the sensation of the chords coming apart as I ascend, trying to muscle them together seems completely wrong. Its just a delicate movement to keep the balance all the way, so it seems. The folds are delicate tissue that take very little muscle effort to move, from what Im feeling and hearing. Thanks for the explanation, steve.

[Matt]

This is an example of bringing the folds together and letting them fall apart. When they're apart, the wrong thing to do, something Ive always done, is to muscle them together. Instead of muscling them together to get a tone out of the airiness, I feel in this example its a subtle awareness and careful, non-muscular shift of the folds to bring them together to vibrate easily and create a tone:

http://www.youtube.com/watch?v=EKKkKtJ5a-M

* Changed the clip.

Unfortunately you cant hear it well on the recording but the first few seconds im exhaling, then im consciously bringing the folds together gently and thats when you hear the tone. When I try to reach a high note, my natural inclination is for the note to become just exhaling so I start pressuring my throat muscles together to create a tone - but Im feeling a sensation recently where if I do as I did in this clip, gently bring them together, I get a tone even at high registers, without using any muscling.

[Matt]

Im not doing it very well here, and its late so dont dare sing any louder, but never mind, Im trying to do that in this clip and hit somewhat higher notes with absolutely no muscling at all, but just by trying to keep the folds together as I ascend:

[Steven Fraser]

steve, with that said if one needs to hold on to the adduction process as one ascends in scale to keep the folds together longer and tighter, wouldn't it help us to have extra development in the muscles that assist with that?

Bob: The motion is very subtle, but can be very easily overdone. And if you'll notice, I did not say that the folds have to be held together longer and tighter... I said that they need to be adducted more to compensate for the thinning of the folds.

That said, the idea of maintaining easy but firm adduction during rising note patters is still valid.