Do vocal tract resonances assist a singer's pitch control?

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Wolfe et al (Vocal tract resonances in speech, singing, and playing musical instruments) say in the abstact:
In both the voice and musical wind instruments, a valve (vocal folds, lips, or reed) lies between an upstream and downstream duct: trachea and vocal tract for the voice; vocal tract and bore for the instrument. Examining the structural similarities and functional differences gives insight into their operation and the duct-valve interactions. In speech and singing, vocal tract resonances usually determine the spectral envelope and usually have a smaller influence on the operating frequency. The resonances are important not only for the phonemic information they produce, but also because of their contribution to voice timbre, loudness, and efficiency.

Now, I recently got interested in the role of the vocal tract in achieving pitch accuracy. Regarding this aspect Wolfe et al discuss it in the case of wind instruments but not in singing:
Wind instruments use the breath of the player as their energy source, and so the vocal tract can be intimately involved, and its resonances can contribute both to timbre and to pitch control.

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Question: I would like to know whether it is true that a singer's
vocal tract resonances ... have a smaller influence on the operating frequency.
as this paper states.

Personally, I suspect that opera singers, for example, could be exploiting vocal tract resonances when they hit each note spot on with apparently no effort. (Also vocalists from many other traditions e.g. Indian classical music).

Example: https://youtube.com/clip/UgkxiXljldtdS955hi4D4V97d6DuYDCKXq9d?si=fh9HBsnREvqaHu3J

My guess is that it is not merely a feedback loop where the singer's brain compares the heard pitch with the target pitch and makes rapid corrections.

I will be looking for more literature, but someone here probably knows more and can point me to good references.
 
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Mariah Carey has a 5 octave range. That's 60 notes. Do you think her vocal tract has 60 fixed resonances that just happen to be properly spaced? This seems unlikely.

I think the model of a trombone - resonances over a continuum - is more accurate.
 
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Swamp Thing said:
I suspect that opera singers, for example, could be exploiting vocal tract resonance
Agreed. The basic oscillation of the vocal cords will be very low Q and easy to 'pull' by loading with a cavity. It can't just be a tone generator plus a broad band filter.

The resultant pitch has to be from a combination of muscle tension on the cords and some very clever manipulation of the air spaces around there. Training gives professional singers a massive advantage.
 
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The lowest frequency in the male speaking voice is about 300Hz, corresponding to 70cm, so I suppose the vocal tract is long enough to have a resonance this low. But I cannot see how the track can be tunable over a frequency range spanning a few octaves.
 
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tech99 said:
so I suppose the vocal tract is long enough to have a resonance this low.
I would imagine that the vocal tract would act more like a Helmoltz resonator (as in a sub woofer) which can resonate at a very low frequency for its size, at the expense of losses.
 
  • #6
I just found this

https://www.phys.unsw.edu.au/jw/reprints/AIRSchapter.pdf

which looks promising at first glance as a source of an answer to my question.

The last sentence of the abstract reads
Finally, (this paper) discusses how singers adjust their tracts using resonance tuning to produce louder, more stable voice with less effort.

By more stable, I presume they mean both amplitude and pitch stability. But let me read the paper in its entirety before concluding anything.
 
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The pitch of a Lion's roar is lower than it should be, according to body size. Male lions achieve this by specifically drawing down and elongating their vocal tract beyond its normal length. This actually cost them energy but it's better than getting into a fight. So all male lions pretend they're bigger than they are. Just like swaggering teenagers.

I think domestic cats may do a similar thing. We had a very elderly tom who used to see off bigger, younger cats just by shouting at them.
 
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sophiecentaur said:
Male lions achieve this by specifically drawing down and elongating their vocal tract beyond its normal length.

I am male, although not a lion. The reason I got interested in this topic and started this thread, is that I recently stumbled on some interesting vocal phenomena while amusing myself by humming along with some music. I was in a playful mood and began experimenting along the lines of the Mongolian throat singing technique and I suddenly "got" how to produce those high order overtones etc. with minimal effort.

So yes --- "drawing down and elongating my vocal tract beyond its normal length" captures exactly what it feels like doing some of the interesting things that I have been diverting myself with, off and on since that first occasion.

Among other things I can now produce a deep purring sound whose pitch can be held very, very stably with little effort. And I can jump up one octave from that initial pitch, and also go up one semitone at a time and hum simple melodies with a level of pitch accuracy that was impossible for me before.
 
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Swamp Thing said:
I am male, although not a lion.
I guess we all use our voices 'at a cost' to other abilities and energy input but the anatomy of a male lion seems to produce lower and louder sounds at the expensive of significant performance in other ways.
 
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Swamp Thing said:
I just found this

https://www.phys.unsw.edu.au/jw/reprints/AIRSchapter.pdf

which looks promising at first glance as a source of an answer to my question.

Have now read through this a couple of times. It offers a wealth of information that is helping to bring me up to speed on this new interest -- nay, this new passion -- of mine. But it doesn't address my hypothesis that singers use certain physical resonances in order to cue themselves in to the exact "position" of each note, and to create a feedback loop that brings them (and keeps them) spot on every time. Or at least, some singers do this, at least during a part of their learning curve, in order to accelerate that learning; and potentially even use it throughout their career.
 
  • #11
Swamp Thing said:
But it doesn't address my hypothesis that singers use certain physical resonances in order to cue themselves in to the exact "position" of each note
A brilliant paper; such a lot of ideas there.
On a personal level, I can agree about 'physical resonances' which we can use for timing / frequency. Some notes just 'feel right' when I tune my guitar. It can feel a bit flat or a bit bright sometimes and a check with the iphone usually agrees. I guess there will be external references when using a musical instrument, such as the resonances of the structure, miles away from E but related in some way that our memory identifies for that particular instrument. Room acoustics in combination with memory could do a similar thing.

As well as forming musical notes with accurate pitch, timing accuracy can be very good with sportspeople. A rowing eight seem to agree on stroke rate to less than one per minute. Swimmers, with bad visibility, can tell exactly when to begin a turn after 50m of energetic strokes.
 
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From all the online searches I have done since I got interested the title question of this thread, this is the first faint glimmer of an affirmative answer : https://newmusicusa.org/nmbx/the-journey-in-performing-microtonal-choral-music-part-1/

.... Which in turn introduced me to the term "Barbershop Singing". If I had read this Wikipedia article more than a few months ago, it would have meant very little to me. But now I find myself nodding agreement with many of the ideas there, because I have stumbled on a phenomenon that singers in certain genres seem to be exploiting to "lock" their voices onto any one of a series of frequencies that fall on a justly intoned scale (in terms of ratios/intervals, not in terms of absolute frequencies of course). The locked-in state results in a very definite and satisfying sensation of "rightness", along with a richer and more frequency-stable sound with less expenditure of air.

With practice one can lock onto more closely spaced pitches (microtones). Without specifically targeting the ending note, I can hop upwards in 12 small notches and end up exactly a just fifth (3:2) from the starting pitch, which I can then verify on a spectrogram in Audacity. Instead of a fifth, it is also possible to go up 12 notches, ascending a staircase equivalent to "C -----> F" (I forget what that interval is called).

And I just found this: Is Just Tuning Possible?
Zarlino, perhaps the most conspicuous champion of Just tuning, had to endure criticism from colleagues at the time. But even Vincenzo Galilei, Zarlino’s “most outspoken and severest critic,” in 1589 had to admit that, in practice, singers do use pure intervals rather than tempered ones:

"… truly, voices sing musical intervals in their true and perfect ratio, whereas most artificial musical instruments play them more or less distantly from their true form."

I am trying to build a contraption using a plastic bottle resonator that will replicate these effects, and also to simulate them digitally. Enough said -- personal theories are frowned upon under our guidelines!
 
  • #13
I bought "Overtone Singing: Harmonic Dimensions of the Human Voice", by Mark van Tongeren.

This paragraph resonated deeply with me (not a pun)...

Scientists still struggle to explain theoretically how the deep drones of Tibetan monks and Turko-Mongol throat singers are brought forth exactly. How can the vocal cords suddenly jump to some mode of vibration that is still lower than the lowest one produced by normal or natural means? Tuvan and other singers have been examined with video endoscopes, laryngoscopes and electroglottographs that measure the internal vibrations and sound energy. Scientists have probed into the matter for decades with varying success. Theories still outnumber facts about the deepest human noises. The German speech scientist Sven Grawunder conducted a particularly in-depth study of the vocal mechanisms of Asian throat singers. He travelled to Siberia to perform a series of analyses and based his conclusions on the data of 69 singers, including 25 he personally hooked up to his various measuring tools. I hoped, with him, for a final answer. But when I asked him in plain language if the new, lowered fundamental can be the actual, real fundamental, he answered : 'That is the big question !' The most widespread idea is that the false vocal folds ('ventricular folds') situated just above the normal vocal folds combine with the vocal fold oscillations at half the rate in what Grawunder calls the 'double cycle mode'. Resonances in the windpipe under the normal vocal folds possibly help to maintain the vibrational pattern (emphasis added).

Edit: Another "resonant" (i.e. relatable) passage from the book...
Tuvan singers taught me that kargyraa should be free from strains. Indeed the technique, when performed correctly, feels like a motor let idle. It does require a certain force, but this does not translate into pressure. In my experience, once it gets going, kargyraa can feel quite soothing and not quite as forced as the higher styles of throat singing...
 
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