Whistle Tone, Overtone Singing and Diplophonic Singing: Can They Be Learned?

Extreme vocals seek out the limits of your voice. Whistle tone refers to singing in the highest registers that the human voice can achieve while overtone singing is something completely different – it’s also a little bit easier to learn. Then there’s diplophonic singing which is something different again. Here, we take a look into the more mysterious side of vocal techniques.

This blog was written by Alfons Verreijt, the developer of the VocalFeedback method and author of the book The Essentials of the Voice.

Note!

It is strongly recommended to combine the techniques explained in this blog with the guidance of singing lessons. Even just a couple of lessons is better than nothing and will help stop you from A) getting stuck and B) damaging your vocal cords.

Whistle Tone

We’ll start with whistle tone, or whistle register which, when harnessed, takes your vocals to the highest pitch range possible – even higher than the falsetto register (as it’s known in the world of classical singing, which is more commonly known as the head voice). There are many famous female artists who have mastered whistle tone, as well as a few men. The most well-known include Minnie Ripperton, Mariah Carey, Georgia Brown, Ariana Grande, Christina Aguilera and Adam Lopez. If you’re not sure what we mean by whistle tone, then have a look at the clips included below.

When you’re able to sing in the whistle register, you have an extremely high pitch range at your disposal. The pitch is so high, it’s not even possible to sing lyrics, so most singers use the technique to perform extreme and impressive vocal runs.

Puzzling Stuff

While science has pretty much mapped every aspect of how humans are able to make sound, the whistle register remains the most puzzling terrain – to the point where no one can say with 100% certainty how it actually works. Vocal coach Alfons Verreijt offers an explanation of why the technique is so mysterious: “When singing whistle tone, the epiglottis is pushed back, just like when twanging. This actually blocks the view of any medical camera that might be able to see what’s happening to the vocal cords, so we have to just guess what they’re doing back there.”

But we do have some knowledge of what’s going on. According to Alfons: “We know that the epiglottic plays an important role in creating the timbre and regulating airflow. This is definitely happening when performing whistle tone. The resonance chamber that lies beneath the epiglottis becomes very small in order to achieve whistle tone, which is how it enables the voice to reach such a high pitch range.” But what happens to the vocal cords? This is the hard bit to understand. The vocal cords combine to form the glottis – the opening between the two vocal cords. When breathing, the glottis is open and when speaking and singing normally, the glottis is closed but not so tightly closed that the vocal cords cannot move, since it’s air passing through the glottis and vibrating the vocal cords that enables us to produce sound. When singing in whistle tone, the vocal cords are largely closed and barely vibrate at all, but at the back of the vocal cords, where they connect with the arytenoid cartilages, a small triangle is formed where air can pass through. This small opening is much like the opening of a whistle and actually works in much the same way. While the opening of the whistle doesn’t vibrate itself, the air within the opening vibrates to create the note. So, when singing whistle tone, the vocal cords barely vibrate or don’t vibrate at all. “This is what we assume is happening, because the sound of whistle tone is much like the sound of a whistle – hence ‘whistle tone’.”

Extreme Breath Support

If you’ve already watched the clips included above, then you’ll have noticed that anyone singing in the whistle register is able to sing for a long time after just one breath. According to Alfons, this is easily explained: “The higher the pitch of a note, the less energy it requires. This means that you need relatively little airflow to produce a whistle tone. However, it does mean that you need a lot of breath support to make sure that you’re not letting the air flow too quickly, and that’s hard work.” What about singing whistle tone in tune? “Pitch control when singing in whistle tone is less direct. Rather than controlling the pitch with your vocal cords, you’re controlling it by adjusting the tension of your glottis.” Is there an artistic reason for using whistle tone? Or is it simply an art; something you can use to impress people with your vocal gymnastics? “I’ll leave that to everyone else’s judgement,” Alfons answers democratically. “Personally I would choose to only use it every now and then for that ‘wow’ effect. Listening to someone singing in whistle tone for a long period of time can get boring. This has a lot to do with the fact that you can’t really sing lyrics in whistle tone, so you can’t really tell a story.”

How to Learn Whistle Tone

Can anyone learn to sing in whistle tone? “Assuming everyone has the same physiology, anyone can learn it. But that’s only in theory,” thinks Alfons. “I don’t think you have to have something special or some vocal abnormality to learn it.” So, say you wanted to add whistle tone to your technique, where could you start? “There are a couple of things you need to do,” according to Alfons. “First, you need to be able to push your larynx back, like you would when twanging. This will allow you to switch from your normal ‘low’ voice or head voice to whistle tone. The idea is to close everything off so that air is only released through a tiny hole.” Alfons also stresses that the larynx must be relaxed to achieve this: “Otherwise, it just can’t happen and tensing your larynx can risk damaging your voice. Even when singing normally you need to relax your larynx.” Since no one knows exactly how whistle tone works, it’s very hard to explain how to learn to do it. This is exactly why Alfons advises using some tried-and-tested methods – namely, by imitating. This will allow your mirror neurons to do the work for you. See more about this below.

Overtone Singing

Whistle register is a fairly common technique within pop music while other extreme vocal techniques are maybe less familiar, like overtone singing. Overtone singing has an important role in specific types of folk music, one of the most well-known being Mongolian throat singing:

There are also choirs that specialise in overtone singing:

Here’s an insane demonstration of what you can do with overtone singing by Anna-Maria Hefele:

How Does Overtone Singing Work?

When we produce a note with our voice, we always create a root note surrounded by a few overtones. When you glide from one vowel sound to another, then a different group of overtones becomes present within the sound. This group of overtones is referred to as a formant. When speaking normally, the root note is so dominant that the overtones cannot really be heard separately. When overtone singing, you amplify a specific formant so you can hear it clearly and separately from the root note. You can achieve this by altering the shape of your oral cavity and by doing that, you can also play with different formants within the same root note. This movement between different formants can even be heard as a separate melody, independent of the root note. Anna-Maria Hefele beautifully demonstrates this by changing the root note here and there. The whistling overtones of this technique is also striking, and even reminiscent of whistle tone and, just like whistle tone, you can only sing wordless melodies without lyrics.”

How to Learn Overtone Singing

Diplophonic Singing

Now we come to diplophonic singing. This is maybe the weirdest end of the extreme vocal spectrum. There are very few people who can do it, and one of them is Lalah Hathaway, the daughter of singer and songwriter Donny Hathaway. Lalah is exceptionally talented when it comes to diplophonic singing – or two-tone singing, which she can call up whenever she wants to. Normally, diplophonia is a sign of vocal damage, and is not something you can necessarily use in a healthy way, but Lalah is evidently an exception. Have a listen to the song Something included below, which she released with the band Snarky Puppy. The standout moment is when Lalah breaks into diplophonic singing at the end and it sounds as if she’s singing three notes at once – but that’s up for discussion, because where two notes sound, there is always a third note present that’s caused by the interference between the first two notes.

Learning By Imitation

Imitation is the oldest learning method in the book. “Our mirror neurons are the key to this,” explains Alfons Verreijt. “These neurons are located in the premotor cortex and the parietal lobes of the brain. The premotor cortex and the supplementary cortex are responsible for programming while the primary motor cortex is responsible for moving. The parietal lobes play a part in integrating sensory information and spatial thinking. Your mirror neurons are constantly alert to your surroundings and can respond extremely quickly – faster than consciousness itself.” Alfons includes this area of neuroscience in his teaching. He goes on to offer an example: “When you record your own vocals and then listen back to the recording, your brain is doing something pretty special. Those mirror neurons are responding to the recorded sound as if you’re making the sound yourself. The response also extends to the body, which does exactly what it would do if you were singing yourself.”

“Mirror neurons help us to learn something without needing to analyse or understand it first. Through imitation, you can learn to sing like someone else even without a precise understanding of what it is they’re doing. When I’m teaching, I always sing along with my students in my head so I can actually feel what’s happening in their body. I am also convinced that people with natural talent also have a lot of really well developed mirror neurons. Even small children learn through imitation: no one explains to them exactly how to walk or talk. They see and hear others doing it and simply follow.”