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omryd

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Sure, the materials play a part in the sound. And it is true that there are many definitions of "chest voice", "mix voice" and "head voice". And at one time, because you can feel sympathetic vibrations in your chest on lower notes, people actually thought that the chest was a "resonator". Like Benny said, the chest plays a very minor part in resonance. Most of the resonance is generated above the folds in the vocal tract. The vocal tract tunes F1, F2 and F3 (the resonance centers) for different vowels.

Here is how a lot of us here on the forum define the different registers:

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You are conflating two inconsistent arguments. One is that the tissue and bones do not contribute. The other is that they contribute, but do not change.

There is nothing special about tissue and bone. Like metal and wood, they affect the sound. It is not just shape and volume that matter. The responsiveness of the container is important. And that does change.

A guitar works by reflection, too. And the responsiveness of the body is what matters. It is not just the shape and size, but the type of wood and thickness of material.

Well, they do contribute. But the contribution is VERY SMALL compared to the major effects. I have been in institutes that have built artificial vocal tubes to generate almost naturally sounding vowels and tones. Those vocal tubes are really just built as tubes with changeable shape and length. The material most of the time is plastic or rubber because it really doesn't matter much. It looks like this:

The real thing is this:

As you can see it is much more like a wind instrument than anything else. All parts that are outside this tube play and absolute MINOR role in terms of sound production. Things like the tongue or palate are important of course because they change the shape of the tube. The diaphragm is important, too (it is the compressor or "engine") but it has nothing to do with resonance.

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What external resonators do you mean? The vocal tube is the thing bordered in white on the lower picture. Everything outside that has just marginal effect.

The main difference between a wind instrument and a string instrument is air compression. A string instrument just uses the air that is availabe. In a wind instrument the air is highly compressed. Thus, wind instruments can be quite loud even without resonance (just think about a whistle).

Also the feedback of vibration after leaving the tube is absolutely minimal, it is just physics. The amplitudes of the echoes on walls or whatever start to vanish so fast over distance that they don't really make a difference. It is the reflections BEFORE leaving the vocal tube that make up for the resonance. And the vocal tube is only really coupled with resonators to which it is connected BY AIR. The transduction in tissue is FAR worse compared to air.

In an acoustic guitar it is different, because the source (the strings) are actually placed outside of the resonator, so the sound enters the resonator through the sound hole and comes back out the same way. In the vocal instrument or a wind instrument the sound source is within the resonator, so the "sound hole" (the mouth) is mainly an exit.

This site has really good info on it:

http://clas.mq.edu.au/acoustics/frequency/vocal_tract_resonance.html

Just to give you some numbers: The acoustic impedance of soft tissue (the resistance against the transduction of sound) is around 4.000 times higher than the acoustic impedance of air. The impedance of bones is around 10.000 times higher. Anything that is not connected by air to the vibrating vocal folds can really be neglected in terms of acoustic effect.

This also makes it clear that the acoustic coupling of the body with its environment can basically be reduced to the mouth when we consider the nasal passage to be closed (which it is for most singers, because they close the velar port).

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On an acoustic guitar the strings are not outside of the resonator. They are attached to the resonator. They influence the Body of the resonator. The vibrations of the Body compress the air inside the body increasing the sound that comes out of the sound hole.

The stronger a connection of the vibrating strings to the body of the guitar the stronger and fuller the sound of the guitar.

The air inside our vocal tract will be influenced by the vibration of the material inside the vocal tract. Lifting the soft palate does not only allow access to the nasal passage but also tightens the lining of the back of the mouth creating a firmer wall that can also vibrate and further compress the air inside.

We can change the shape of the vocal tract and allow for "Tuning" resonance and redirecting air flow to different areas of resonance. But what I am propsoing does not have to do with placing any resonance or redirecting any sound. Just firming the connection of the original source of vibration to the body of the resonators. That connection is enhanced by firm muscles and ligaments that will also transfer to bone.

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Perhaps I am misunderstanding the diagram. I am seeing nodes outside the border. Isn't the nasal cavity outside the border? How come I can hear nasal ring in head resonance?

Ah, okay, the thin line doesn't belong to the vocal tube, it is just the thicker line. The nasal ring, as well as the vibration in the chest, at the brest bone, or the diaphragm are the so-called sympathetic vibrations. Your tissue is set in motion by the sound of the vocal folds. However, because the impedance of the tissue is high this vibration "costs" so much energy that almost nothing is given back to the outside. The vibration is absorbed by the tissue/bones whatever. The nasal cavities respond to certain frequencies being present within your voice, specifically the singer's formant, which is produced by narrowing of the epiglottic funnel.

It is kind of a sensory feedback system: You get nasal ring if you are producing the singer's formant. So some singing methodologies try to incorporate it as a physiological trigger: If you have nasal ring, your singing is good. If you train yourself on that sensory feedback you can get to a point where you can produce nasal ring at will, even though the underlying mechanism is something that has nothing to do with your nose.

However, as it is possible to leave the velar port open "real" nasal resonance is actually possible. And in that case, it even changes the sound (it becomes nasal, which is an increase in spectral content around 800Hz). In most singing techniques, this is not preferred, though.

When I'm talking about minimal effect it is always in relation to "what comes out" in singing. It doesn't have to mean that the energy of those vibrations is low. The actual reason why such vibrations can destroy bridges is that they stay WITHIN the material for the most part and can over time amplify to a degree that they break apart the structure.

For the production of a standing wave it is not neccessary that a complete wavelength fits into the tube, you can find a nice explanation here:

http://clas.mq.edu.au/acoustics/frequency/resonance.html

The first resonance of a regular tube boils down to the formula 343 / (4 * L), where L ist the length of the tube. For the vowel /schwa/ the vocal tract takes almost the form of a perfect tube and an average length of the vocal tract is around 18 cm, which puts the first resonance at 476 Hz, which is F1 for the vowel /schwa/. The upper resonances are odd multiples of that frequency, so F2 is at 1429 Hz, F3 is at 2380 Hz.

One primary actor in terms of length is the larynx. You can rise or lower the larynx which decreases or increases L, the length of the tube. Thus rising the larynx rises the formants (resonators) and lowering it lowers the resonators in frequency.

Of course that is the simplistic view. On other vowels than /schwa/ the vocal tube doesn't resemble a perfect tube that much and the resonators are not in the regular pattern of F2 = 3*F1 and F3 = 5*F1. But while calculation is hard in that case, you can still measure the formants of other vowels based on spectral analysis, which gives us a better picture on how the action of mainly the tongue plays a role in rising or lowering single formants (resonators).

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On an acoustic guitar the strings are not outside of the resonator. They are attached to the resonator. They influence the Body of the resonator. The vibrations of the Body compress the air inside the body increasing the sound that comes out of the sound hole.

The stronger a connection of the vibrating strings to the body of the guitar the stronger and fuller the sound of the guitar.

The air inside our vocal tract will be influenced by the vibration of the material inside the vocal tract. Lifting the soft palate does not only allow access to the nasal passage but also tightens the lining of the back of the mouth creating a firmer wall that can also vibrate and further compress the air inside.

We can change the shape of the vocal tract and allow for "Tuning" resonance and redirecting air flow to different areas of resonance. But what I am propsoing does not have to do with placing any resonance or redirecting any sound. Just firming the connection of the original source of vibration to the body of the resonators. That connection is enhanced by firm muscles and ligaments that will also transfer to bone.

What you are talking about is intrinsic anchoring. It helps greatly in stability because it supports the muscles around the larynx, but as said above the direct influence of the tissue on sound, stiff or loose, is minor. The main effect of lifting the soft palate is a switch in space and shape of the vocal tract, indeed an extension of the tract towards the nasal cavity, but not inside the nose. This action actually doesn't even create a resonating effect, but a dampening effect (it makes the tone more dampened and rounder).

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As I wrote above, for a standing wave it is not neccessary that a full wave fits into the tube. It doesn't have to be the fundamental that forms the standing wave, it can be the harmonics, too.

What Felipe ist trying to say that the actual emission from the folds is not a sine wave, it has harmonics. And those harmonics are what forms the standing wave in the vocal tract. You can see that in Figure 10 on the picture I posted. The uppermost part of the figure shows the fundamental, the lower parts the harmonics.

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Ah! Now this is different. Are you saying that sensory feedback can cause resonance?

Sensory feedback can be a tool for learning. So indirectly, yes. The sensory feedback can cause you to make adjustments that create resonance.

I have read through the article. It is very elementary.

It still shows how the overtones of a sound can form a standing wave, which is what I'm trying to explain. It is not neccessary that a full wave of the fundamental fits into the vocal tube.

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As I wrote above, for a standing wave it is not neccessary that a full wave fits into the tube. It doesn't have to be the fundamental that forms the standing wave, it can be the harmonics, too.

What Felipe ist trying to say that the actual emission from the folds is not a sine wave, it has harmonics. And those harmonics are what forms the standing wave in the vocal tract. You can see that in Figure 10 on the picture I posted. The uppermost part of the figure shows the fundamental, the lower parts the harmonics.

;)

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For this linear model, a quarter wavelength must fit in the vocal tube. The emitted wave is a linear superposition of sinusoidal waves. The fact it may not be sinusoidal is a red herring. If the fundamental doesn't fit, then it won't be amplified and will be missing from the output.

So, when we sing C3 (or anything below B4!), the fundamental would be missing. Is that what you are claiming?

Why should the fundamental be missing when it is not amplified? It is still in the signal. It is a well-known fact that in singing the fundamental is most of the time not the dominant element in the output. And the reason is exactly that the fundamental is not amplified in the vocal tract, it just passes through like it was produced by the vocal folds.

Here is a nice picture that roughly shows which amplification is available at watch pitch. It shows E4 as the lowest note where amplification of the fundamental is possible, and that is only with an artificial increase of vocal tract length (lowered larynx), as is done by some classical singers.

In rock singing amplification of the fundamental really starts in the B4/C5 area most of the time. Below that the dominant element in the output is always a harmonic, mostly H3-H5 on the lowest notes and H2 in the middle area. When the fundamental starts to dominate the voice gets "fluty" in quality. When amplification of the harmonics vanishes the voice starts to sound like a whistle.

It is as simple as that: If you can amplify the fundamental while singing B4 in your vocal tract, you can also amplify the 2nd harmonic while singing B3 (which is B4) or the 3rd harmonic while singing B2 (which is B4). In practice you will amplifiy higher harmonics than that, so you don't even need the maximum length of your vocal tract. Instead you will make the larynx rise on higher notes.

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Benny

Do you have a link to the document containing your last schematic?

http://www.google.de/imgres?hl=de&biw=1486&bih=838&tbm=isch&tbnid=zQIExNm9DE4dNM:&imgrefurl=http://www.phys.unsw.edu.au/jw/voice.html&docid=leVW30_UorkvVM&imgurl=http://www.phys.unsw.edu.au/jw/graphics/resonancetuning.gif&w=1123&h=352&ei=wQ1yUo-3Earn4gTr_oDQCA&zoom=1&iact=rc&dur=248&page=1&tbnh=84&tbnw=270&start=0&ndsp=39&ved=1t:429,r:9,s:0,i:109&tx=173&ty=35

And a link to the "well known fact".

Not really. This has been around for so long that it's probably not even worth making a paper about it. But you can just try it out yourself. Sing something and then put it in a spectral analyzer. As long as you are not singing falsetto, it will not be the fundamental that is dominant, especially not in chest voice.

You can also take almost any arbitrary picture of a spectral analysis of the voice and see it. Here is one from the link above:

The border between M1 and M2 is around E4 in that picture. The fundamental does become comparably strong to H2 somewhere in the middle of M2, not even really dominant.

E4 still requires a 25cm vocal tract.

How do they prove that E4 is the lowest note where amplification is possible?

In that experiment they measured the vibration of the folds themselves using an EGG. Then they recorded the "output" and compared the two in terms of spectral content.

The graphs in the second line show the resonances of the vocal tract on a certain vowel. The resonances (R1-R4) are identified by the broad peaks (not the small spikes!)

You can also just search for formant charts on the web that show the average resonances on certain vowels. The vowel with the lowest 1st resonance is the vowel OO, which has it around 300 Hz. Which means on the vowel OO (which makes the tube as long as possible) you can have amplification of the fundamental in the area around D4/E4.

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Thanks for the links and info, Benny. Very interesting.

I don't see anything that measures absolute amplification of a frequency, or even how you could do it.

The graphs you specified show only relative information of the filter action in the source-filter model (as I understand it, so far). The shape of the graph may characterize the vowel dependent filter matrix, but I don't see any absolute amplification information, here. Even the units are dimensionless.

What is the absolute information you are looking for? The unit of the Y-Axis is dB, the unit of the X-Axis is Hz. So you get information what frequency gets boosted by what amount of dB. Of course it is always relative to the source signal. An increase of 20 dB by the filter on a certain frequency (which is thought to be roughly the maximum on certain vowels) means that the output sound pressure is 100 times bigger than the source sound pressure on that given frequency, so what absolute information do you need? The absolute sound pressure depends on the source volume and that is an artistic choice by the singer. Amplification is always relative to the source.

And the whole thing is complicated by the fact that the base axes (eigenspectra) are not sinusoidal. The fundamental in the source does not become the fundamental in the output in a nice scalar fashion. That alone would account for why the fundamental may not be dominant in the output.

If the fundamental would not be the fundamental in the output the note would be off pitch or percieved as being a different pitch. This CAN actually happen with some vocal tract shapes, it is called "overtone singing", a case where the vocal tract indeed is set up in a way that one of the harmonics (or sub-harmonics) becomes the fundamental in the output.

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The non-linear source-filter-model is even more complicated. It especially explains why we tend to "break" when formants pass harmonics. As Felipe points out it is even more of an indication that there are really different registers where you have to adjust when entering them.

To come back to the original point: Alle that stuff, regardless if you take the older linear model or the newer non-linear model still has in common that everything that resonates or enhances the sound still happens in the vocal tract, not in the head, not in the chest or anywhere else.

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Judging by the Luthier site that was linked in earlier, a number of instruments can create what is known as middle C (C3) without having the 2.6 m length. In that table, that measurement was related to middle C on a guitar (second string, 1st fret.) I have 4 guitars. Two of them are electric, with no self-contained resonating body and require an amplifier (my Fender 85, which puts out 200 W rms, I can rattle the frame of the house.)

Two acoustics, one that has a broken interior brace and one that I play. Anyway, ain't now way either of them is 2.5 m. I am personally 2 m tall. And I am taller and bigger than the guitar. And a singer, without a 2.6 m vocal tract can sing a C3 in tune with the same note being played on a piano, for instance.

To an extent, any act of resonance also acts like a filter. For, by giving this or that frequency prominence in volume, others are not heard because of the masking effect of some equipment and most especially of the human ear. It hears the loudest sound first and mostly.

This was an interesting page, though you have to scroll down past the trumpets to find the human voice.

http://fiziks.net/Music%20Sample%20Chapter%20Seven/musicsamplechapter7.htm

Simply put, the human voice does not require 2.6 m to resonate a C3. In actuality, the volume is inversely proportionate.

Usually, I just like to stick to my oversimplification. A note is a wavelength. In the right size/shape resonating cavity, it doubles upon itself, creating twice the amplitude, which creates a logarithmic (non-linear) increase in volume.

Or, to tick every one off, :lol:

Note in the head.

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So, yes, coming back to the point, neither model postulates chest or diaphragm feedback. Neither are the models insisting that their assumptions are accurate or that their predictions are reliable.

Of course, it's just how science works. We will never be able to shoot for "the real thing". If anything, we can come closer. Nevertheless, it is the most reliable source we have when we try to communicate about singing.

Felipe's comment, if I understand correctly, refers to your statement that there is no such thing as a coordination named "head voice" that the guy in the video enters.

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I don't always accept what is in an article. In the one Ron posted, my eyebrows shot up when I read this..

..later in the article, surprise! surprise!

To me, this is kind of intuitive. The volume/shape model is lacking. You can't just ditch the experience of your ears and your intuition, and defer to a mathematical model.

Exactly and as others before me have pointed out, just because you feel a vibration in, for example, your eye sockets does not mean that is where the note is resonating and what you are feeling is a sympathetic vibration. Resonance is something that happens and the true proof of the pudding is what happens to the note, objectively.

So, let's say that singing a C3 is accompanied by a buzz in the big toe on my left foot. Does that mean I am resonating there? Of course not. It's just an effect in the body that happens when the right thing is happening simultaneously that is creating proper resonance for the note.

How does an acoustic note resonate in an acoustic guitar? I know exactly how volume is produced in an electric guitar and the circuits of the amplifier I mentioned before and there are some ways it differs from acoustic amplification and I won't bore others with that difference. And if you think about it, nothing acoustic actually reverberates that well on spongy material. It needs soemthing a little more rigid or resilient is probably a better word, but not just lax velvety flesh. Which means your brighter resonances are achieved by harder surfaces, like a brass instrument.

In which case retracting the soft palate, which may or may not access smaller resonating spaces in the sinus cavity, and I like to think it does due to the physical research of Dr Fillebrown, it is also revealing the back side of the hard palate, as the buccal opening changes from the singer's smile that retracts the soft palate and uvula.

And all this makes me think of Bob's mention of "throat-shaping." Elements of placement, if you will. Which is something I engage it, to an extent, as well. Hey, whatever gets you through the night. And I agree with you, Kicking, in spite of my own redneck predilection toward math, that one must also accept the intuitive experience and not simply rely on a mathematical model. Get redneck with it. Use the math model to gain an insight, then apply the insight and let the rest of the math sit.

In 3-phase power calculations, I lose most new guys when I show the solution by Pythagora's Theorem. Just about no one can follow me through the spherical trigonometry explanation (which is actually more accurate and physically descriptive of how 3 phase power is generated. Finding the multiplier needed in the divisor is a cosine of the angle between two legs of voltage, which will always be 120 degrees in american 3 phase power.) As long as the guy divides power for 480 V by the divisor of 831 and divides power for the 208 V side by 360, he is functionally doing the same thing as I am with all that high-falutin' math.

So, I give myself the same "helper" advice when singing. Ultimately, how I describe it mathematically will only be of value to a few people. Better to judge by the result. And the result is something you can hear. And feel.

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I also think that vibrations and "feelings" of resonance can change and that is why the objective quality of the note must supercede even where you think you are feeling it, even though I would also concede that if you have a feeling and the note is objectively good, go with that. For example, when I would do really high notes, I would either feel a tickle at the "top of my skull" or a rattling of the eyeballs. Not true descriptors but close enough. Now, I just feel a "ball" behind the sinus. Keep your eye on the ball, as it were. Does it mean that my new imagery or sensory location is more accurate? Like you said, it may not ultimately matter that much. And yes, a sound wave can travel through tissue. And material. Like the rumble of a passing freight train. And there may be some ancilliary resonances happening with that, audible or not. So, it does not mean that resonance in other parts of the body do not exist. And it does not mean that those resonances contribute. However, they may be signs that what you are doing is right. And that is all a singer has to go by. It's not like playing a guitar, in that sense. I can tune the guitar by tuning the first string at the 5th fret to A - 440. I have a metronome that has a pitch generator that produces a true 440 A. And then I tune the guitar "backwards" from there. One cannot do that with the human voice. So, we have to go by whatever indicators we have, such as our ear and where we feel it.

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Interesting discussion guys.

Question for you guys that think resonance for chest voice is produced in the chest / diaphragm. Why is it that I can keep the strength of the C3 fundamental exactly the same at the beginning of a long note - where my diaphragm is in one position, all the way through to the end of the note when the diaphragm is in a totally different position shape, and the lungs are practically collapsed? I'm not saying your theory is incorrect, but just testing it.

The chest, rib cage, diaphragm, lungs, are all in flux and changing shape while singing. If the body of an acoustic guitar was allowed to change like the human chest it would definitely change the strength and resonance of the notes. That's why Violins, Violas, Cellos, etc. are different fixed sizes - the size of the resonating cavity plays a huge part.

Also, why wouldn't we see evidence that large chested humans are better at singing Bass? I've got a friend who is smaller than me that has a very low resonant voice. I cannot resonate low frequencies very well at all but my chest is larger. I think the big difference here is the size and depth of vibration of the vocal folds. (look at the guy who won American Idol - Scotty McCreery - the Bass country singer? he is not a large chested human)

Also - Explain this one - Why is it that when I have a Cold, I can reach some very low notes, and resonate very low frequencies. It's like I become a Bass for a few days. My vocal tract didn't change? (in fact it becomes more constricted) My Chest didn't become bigger? My Diaphragm isn't infected and swollen? However, my folds did become inflamed. This supports the notion that the it's the size and depth of fold vibration that has to do with the strength of the C3 fundamental.

Just testing your theories here with some real life experiences.

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