I must be mental to write about this mixed voice
Mixed voice is such a common term so why would it be a nightmare to write about? Well, that’s because it means such different things to different people. Is it is a voice quality, or is a particular set of notes? Could it be a gear change or the area between chest voice and head voice? Here’s one definition from about.com
“about a 50/50 split in resonance”.
What does that mean? How do I split my resonance?
I can’t answer either of those questions without yawning, or starting the entire post again having got nowhere. Instead let’s cover mixed voice in the acoustic sense, which is just one way to attempt to describe this ambiguous little blighter. I will absolutely post something on the vocal fold story of mixed voice soon, but that’s another ball game altogether!
Let’s get physic-al!
Before we begin, I need to sound the ‘nerd alert’. This is a definition article with a little bit of science babble. Not a short instructional piece showing you how to do it. That’ll come later… just so you know 🙂
Now that’s out of the way, I honestly don’t feel like I can describe the resonance phenomenon of mixed voice without potentially alienating you with an unsexy subject – physics. More specifically, acoustics.
However, for a true understanding of what everyone is rattling on about when they talk ‘mix’ you NEED to know this stuff. It also handy to know more about vocal acoustics if you want the ability to discern singing truth from singing BS. That’s handy when there’s so much of it around!
Let’s get our head around harmonics for a sec. Stay awake…
Our vocal folds begin to make sound by interrupting the airflow that leaves our lungs. This interruption causes pressure to build up underneath the vocals, which causes them to vibrate as the air eventually bursts through. For the record, this pressure build up and vibration thing happens in a fraction of a second.
The speed of vocal fold vibration is determined by the vocal fold’s tension, which is adjusted by the muscle in our larynx when we sing higher or lower. You exercise this tension-changing ability every time you sing a melody and speak expressively so it’s not a very technical thing. We just do it, although extreme pitches and tensions are what we have trouble with mostly. That’s where teachers come in to help out.
ARE YOU STILL WITH ME???
As the vocal folds vibrate in singing, they are constantly parting and colliding, many times per second, in a constant cycle. As they collide, their mucosal covering also vibrates as a result of the collision. In a better description, the covering ripples like a kind of vocal jelly. Those ripples allow little puffs of air through at varying speeds. These little puffs send vibrations though the air molecules in our throat and mouth, and eventually into the outside world. Our ears are the receivers for that signal, and therefore we have sound waves!
So, in essence, harmonics are sound waves created by these little puffs of air in each vibration of the vocal folds. The amount of vocal fold vibrations that happen in one second is decoded by our ears and brains as the pitch. This measurement is known as the frequency, displayed as Hertz (Hz). If we sing an A4, that equates to 440Hz. That is, 440 vibrations per second!
Back to the puffs of air that create harmonics, because they come from the same event (IE, vocal fold vibration/collision) our brain decodes these extra parts of the sound wave as the tone colour of the note being sung. Because the puffs of air ripple so much faster than the vocal fold vibration, they send off much higher frequency elements in the sound wave. Up to thousands of vibrations per second and beyond.
To summarise harmonics…
It’s such a b*tch to grasp harmonics. It’s essentially lots of different pitches being created at the same time, from the same source, but we only hear one consolidated sound! On saying that, it’s lucky we only hear one. It saves us from being overwhelmed by this barrage of individual sound waves. Instead, we just hear two things: the amount of vibrations per second (the pitch) + the harmonics generated in that vibration (the tone colour). Thanks brain!
Moving on from harmonics, we need to march on into spaces and resonance…
If only this was about chocolate 🙁 But alas… back to physics
The thing about spaces is that they preferentially reinforce sound waves, making them more intense. This is purely because spaces can change how sound waves travel through the air in them. Their size also changes how and when these waves reflect around in the space. A bit like how a room, and what it’s made of, can change how long an echo bounces around the walls for. As you’ve probably guessed it, if you were to scream into a wardrobe it wouldn’t be very resonant.
Don’t ask why I scream into my wardrobe.
Larger spaces boost lower frequency vibrations, and hence lower pitches and harmonics. Smaller spaces reinforce higher frequency vibrations, and hence higher pitches and harmonics. In singing, a larger space would be considered as the throat and our lower notes may feel like the resonate there. A smaller space would be the mouth, and that space is capable of resonating much higher pitches.
Interestingly, vowels change the shape of both our throat and mouth. So, these spaces are capable of being many different sizes! That means they are also capable of resonating many different frequencies. Oh the wonder of it!
The ‘F’ word
The preferential frequency, or pitch, that a space will resonate is called a ‘formant frequency’. Formant for short, which is terminology you may have come across before. If the space changes shape, the formant (and hence the pitch frequency that it will boost) will also change.
If you’re not too bleary-eyed from the last 934 words, let’s get to the myth.
I’ve already banged on about the throat being able to resonate lower pitches, which is significant here. Certain harmonic energy in our voice becomes too high for the throat to resonate. It’s just too big and suited to low notes!
If we keep raising pitch, we will reach the point where this energy stops being resonated and doesn’t contribute to our tone colour anymore. We can feel and hear that as it happens. You’ll know the place… around E4/F4 for guys and A4/B4 for girls, singing an UH vowel.
Provided you’re not massively straining, this transition will be felt subtly, but obviously, without a big break or crack.
I know what you’re thinking though…
“But I’m not resonated anymore… waaaaaaaaaah”
You are, but it’s just not the harmonic energy that was bouncing in the throat. There’s plenty of other harmonic energy knocking around in the other spaces of the vocal tract that contribute to your sound. Otherwise, you’d be completely inaudible! We just feel the one described above much more distinctly, so we have latched on to it.
We always have the vowel on our side too. Because vowels change the shape of the throat and mouth, they are very useful tools for adjusting which pitches and harmonics we can resonate. That’s why some vowels are impossible to sing high up, and some help us negotiate the passaggio.
Is that it???
Pretty much. Entering the acoustic world of mixed register basically boils down to:
Certain pitches and harmonic energy getting too high for the throat space to resonate, so acoustic energy changes.
No mixing in sight, really. Because there’s no mixing, the teaching industry is beginning to avoid the term ‘mix’ because it is so misleading.
This is on a strictly ‘need to know’ basis
I usually battle with myself when writing articles like this. I think to myself, probably like many voice teachers reading this:
“Who honestly gives a sh*t about physics???”
Or the more polite version:
“Actually how useful is it knowing this?”
For teachers who want a better understanding of how voice works and a good BS meter for taking in new material, I feel it’s essential to dig into science. It also helps teachers avoid unhelpful or inappropriate vowel choices. That makes getting to the end game much quicker for everyone.
When I sing I don’t think much about this at all, granted. But many of the tools that got me where I am today were based on this knowledge.
For singers and enthusiasts, it could muddy the waters to know all this stuff. You’re in serious danger of analysis paralysis! My view is that you are better off experiencing it with someone trained to create a scenario where you can. That way you can name it whatever you want. Mixed voice, monkey voice or “my god I can’t feel a thing” voice. Please take this information as purely a geeky indulgence without losing sight of the instinctive, experiential nature of singing training.
It doesn’t stop there…
All of that up there is about resonance, but there’s another massive chapter in the mixing myth; the vocal folds. This is the theory that the vocal folds themselves can create a mixed setting, which is aside from resonance. Stay tuned for that article, which will be coming soon once I’ve recovered from this one 😉
Please do contribute to the conversation below if you’re a singer, mixed voice enthusiast or vocal coach. Contact us if you have any further, burning questions!
Chris is also a writer for iSing Magazine, a founder/presenter of The Naked Vocalist podcast, a voting member of Pan American Vocology Association, and a teacher trainer/vocal coach with the Vocology In Practice network.
All that aside, he's a pure and true music fan with a penchant for Donny Hathaway and songs about heartbreak.
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