Singing Undertones, Subharmonics, and Subtones

How does one learn to sing those seemingly super-low tones? Some people are as obsessed with low notes as they are with the high ones. For whatever reasons, the extremes of anything are attractive. 

Vocal infrasonics can be heard in various traditions: the yang chanting used ritually among some branches of Tibetan Buddhism; the folk music and throat-singing of Tuva (kargyraa) and Mongolia (kharkhiraa); the liturgical music of Sardinia (in the tenore bass voice): alongside the umngqokolo overtone singing of Xhosa women; and either occasionally or continuously in the epic songs of the Altai, Khakassia, and Sakha Republics. 

But the ability to produce subtones is inherent in the human vocal apparatus; consequently, this vocal technology also arises spontaneously and radically, which is to say, devoid of roots in any of the above-listed traditions.

I used to tell people that to sing subtones they simply had to hit "second puberty". Though the joke has since grown tiresome, there is truth to the onset of a lesser known secondary pubescence. At about the age of 26 years, the human brain typically ascends to another plateau of cortical development, whereby the pre-frontal cortex fully matures. Think back (or forward) to your twenty-sixth year or when-a-bouts. What was happening at that time? How did you feel? Anything change?

Perhaps at twenty-six your voice didn't start to sound like a chainsaw at the bottom of a well, but still, maybe we should rethink the concept of only one puberty, only one turning point in the ongoing development of the remarkably intelligent organism that is human body. 

Overtones and Undertones

 

Overtones exist. There is a clearly observable and measurable series of harmonic overtones that is inherent in periodic sound vibration. Overtones go over the main note, but is there a series of tones that go under the main note? 

Is there an undertone series? 

In formal acoustics, the undertone series remains a theoretical construct, not an actual acoustical phenomenon. To date, no one has produced evidence of an undertone series, a true mirror inversion of the overtone series that sounds simultaneously with the fundamental frequency (With singing, the fundamental is the actual note sung by the vocal folds).

 

Theoretical Undertone Series to the Fifth Partial

What is that low tone if it is not an undertone? I prefer to call it a vocal subtone, as it is caused by the oscillation of tissues that lie above the vocal folds. We use the vocal folds for everyday speech and song. The tissues above these actual focal folds are known as the false vocal folds, and you can see them on the diagram below, which is a cross sectional view of the larynx.

When the actual vocal folds are set into periodic vibration with a highly tensed glottis, the false vocal folds are pushed together and slightly upward toward the back of the throat. I have imagined that when these slimy little flesh curtains are set into motion to produce a subtone, they look and feel like puckering lips. 

When set into motion, these false vocal folds vibrate most optimally, with maximum amplitude and consistency, at exactly one half the rate of vibration of the actual vocal folds. For example, if your actual vocal folds are singing an A 440 Hz and you set your false vocal folds into optimal vibration, you will produce a strong subtone of 220 Hz simultaneously with the 440 Hz tone of your actual vocal folds. Thus, you are producing two distinct oscillations spaced one perfect octave apart. 

For this reason, I prefer to use the term subtone instead of subharmonic or undertone to describe this phenomenon, as the secondary tone is not a partial harmonic of the actual note sung, but a distinct fundamental tone unto itself. Furthermore, being a tone unto itself and not just a partial, a subtone also has a corresponding overtone spectrum. 

Remember that overtones are parts dependent on the whole, which is the fundamental vibration. Overtones do not have overtones, nor should undertones have overtones.

Does this remove the mystery from subtone singing? Not at all. We're merely taking out the mystery and then putting it right back in again. 

No one knows exactly why the subtone vibrates so supremely at exactly one octave below the fundamental. Resonance might begin to explain it. The false vocal folds might absorb more energy when the actual vocal folds matches the resonant frequency of the false folds. However, one can sing a whole scale in subtones, which indicates the false vocal folds have an atypically wide range of resonant frequencies. Furthermore, the vibration of the subtone far exceeds the intensity of the vibration of the actual tone, and the false folds feel and sound as though they are not merely absorbing energy, but producing it independently.

There you haven't it: the mystery remains. 

How to Sing Subtones

1. Sing any tone naturally and slowly slide it up a little ways, and then go all the way down to the lowest note your can sing comfortably. Hold it.

2. From that low note as your base, sing up about a perfect fifth (the opening interval of the Star Wars theme, the Superman theme, the E.T. theme, or the opening notes of just about anything by John Williams). 

3. Starting on that note about a fifth up from your lowest, begin to hum. For a few minutes, just practice holding that hum steady to get comfortable with your note.

What follows is the hard part, and no "how to" explanation will be universally applicable to each individual, but try this anyway:

 

4.  Pretend you are pushing an immovable object with all your strength and then grunt. Sustain the grunt as you sing your note. You should be feeling a lot of pressure building up beneath your throat, in your lungs, and all the way down to your lower belly. 

5. With that feeling of pressurization in your torso, imagine you are pushing up from the back of your throat where you feel normal vocalization while pushing down from somewhere a ways behind the base of your tongue. This is a difficult sensation to feel and remember, and most people feel more upward push from the back of the throat than they do downward push from the base of the tongue. There should be a sensation of the back and front meeting somewhere in the middle, where we find the false vocal folds.

6.  While pressurized and pushing the throat, begin to do the grunty hum and then add just a touch of cough and hack while continuing to sustain your note.

7. Slowly and carefully adjust all the physiological parameters (degree of tension, placement of tension, pitch of your note, vowel, mouth open, mouth closed, seated or standing, morning voice or night voice, etc.) until the subtone appears. When it does appear, don't chase it. Take a moment to stop and become aware of how it felt and sounded. Much of the learning here is in deeply internalizing a physiological memory of the sensation. 

When you achieve a consistent subtone, you will know it. The sound will be strong and it will seem to just lock into place on its own. 

Three Common Mistakes 

1. Going too deep. When singing a subtone, you are not singing a low register note with the actual folds. The actual folds are actually singing a relatively mid-range note, and the false vocal folds are resonating at one half the rate of the actual folds. Similarly, beginning subtoners often associate the deepness of the subtone with deepness in their body. As a result they tend to put the sound too deeply in the throat to produce a gravelly rattling that feels like it is going into the chest---it's kind of an old-man-with-his-orange-juice-in-the-morning sound. But the vibration of the subtone is actually above the vibration of normal vocalization. Send your awareness of the sensation upward, not downward. However, also keep awareness in the root of your body, at the base of your belly and even lower, from which the energy of this sound must come. I know it is confusing when you think about it, as there are lots of paradoxes in this kind of singing. Doing will make it clear.

2. Vocal frying. One can produce uber low vocal tones by loosening the glottis to regulate the incoming puffs of air. These bubbly pops can be regulated to produce a false bass register, sometimes known as strohbass. In the morning, you can really get those low pops on or around the vowel "uh", and you can make them go faster and faster until they resound a steady low tone. The vocal fry sounds primarily from the slack closure of the actual vocal folds. The sensation is completely different from subtone singing, which is an intense and simultaneous vibration of the tissues above the actual vocal folds.

3. Over-Practicing. When I first started learning subtone singing, I did it for about 3 hours the first day, 6 hours the second, 8 hours the third, and none for the the 5 days that followed because my voice disappeared into infrasound. For a while I was speaking so low I could only speak in rhythm. The moral of the story is, you must proceed very carefully and patiently. Your false folds have lain dormant for most of your life, and now you're asking them to wake up and vibrate. With gentle and moderate daily practice (no more than 7-10 minutes a day when first learning), the false vocal folds can begin vibrating freely and with no tickling or discomfort. The beginning subtoner, however, must endure some mild tickling and slight irritation when setting into motion the tissues of the false vocal folds. But with a little time, even the most intense sounding subtone vibrations will not and should not hurt if done properly. In this context, and perhaps many others, doing properly means simultaneously relaxing some areas of your body while tensing others.

Still Mystery

Finally, though at first you may have no idea how to do this kind of singing, you will have no doubt whatsoever when you have done it. The subtone will resound with such purity that you will just know that something mysterious still lies at the back of your throat.