I sympathize with those who ask "how can I learn to do that?" I know they seek the same feeling I sought. What follows here is a rather incomplete list of suggestions, affirmations, and aphorisms which are in no particular order, but are most certainly not "random" to use the parlance of high-school times. "That was so random," the young people say, and I do love them all for it. However those "so random" acts to which they refer are usually more deliberate and focused than anything else they have done all day--a foray of full intention, a precise and directed line against the backdrop of a quotidian wash. Randomness should not be confused with spontaneity, but either way--either one--I think we need a lot more of it.
I hope the following list leads you closer to the kind of singing you want to do and the kind of feelings you want to have. Please know, however, that there are no magic words that can give you the skill. You have to play, experiment, observe, and adjust.
1) You can teach yourself. Though learning to overtone sing without a teacher might seem impossible, many adepts have acquired skills while sitting all alone in a room. I learned by listening to recordings of overtone singers from Tuva, Mongolia, Central Asia, North America, and Europe. Within a day or two of obsessive, continuous practice, I could imitate most styles with a reasonable degree of similarity to their sources. I have taught some individuals who catch the "knack"of a style within minutes, and it is very much a "knack" because there is an indescribable trick to turning on the sound, and when you get it, you'll have it. I believe I got the hang of this with some ease because I'd played the trumpet and other brass instruments for many years before singing overtones. Other brass players have caught on quickly as well, and the "jaw harp"--specifically the tongue placement when playing--shares some very salient parallels with overtone singing.
2) Imitate other singers, but sing like you. All humans, regardless of age or gender, have the same digestive and respiratory components comprising the vocal apparatus. Each voice is unique and truly inimitable. You can waste a lot of time trying to sound like someone else, while your own intrinsic sound is there waiting for you to discover it. Muster the courage to work with your inherent sound because no one else in the world has what you have, and therein lies its value.
3) Listen as much as, if not more than, you sing. Maintaining enthusiasm is necessary to attaining skill and producing meaningful sound--"music" if you dare. But desire can keep you from your goal. In making efforts to produce high, ringing harmonics, the novice strains, pushes, pulls, and all around fails to observe the overtones that are already present in his or her natural singing voice. I recommend first listening for the harmonic overtones in your natural, uninhibited singing voice and, when identified, concentrating intensely upon them. By listening carefully, one learns that there is no need to force the emergence of what is already there.
4) Practice intoning vowel sounds while cupping the hand to the ear. Beginning on a pitch in your medium to low register (probably the frequency range at which you speak), intone around the vowel triangle, moving as slowly as you possibly can and breathing comfortably as needed. As you sing, cup your hand to your ear with the palm held slightly away from the jaw line. The cupping of the hand amplifies the higher harmonic overtones that characteristically fall away the moment your sound leaves your mouth and enters into the air in front of your face. I have observed this hand-to-the-ear technique at use in several of the world's traditional singing traditions. Furthermore, in my opinion, the gesture of putting the hand to the ear helps to redirect awareness from the reactionary mouth to the responsive ear.
5) Practice the three "voices" and making transitions from one to the other. Almost any overtone-singing style is executed using one of three voices. The "voices" are more than just three differing vocal timbres. The first voice, the "neutral"or "natural"voice, uses no more laryngeal tension than is necessary for speech. Second, the "throat" voice (known as the khoomei voice in Tuva and neighboring regions in Central Asia), uses an immeasurable but clearly audible amount of increased tension in the larynx. Technically, the throat voice is made by increasing the length of the "closed phase" in each open-and-close cycle of a periodic frequency. The throat voice is not unique to Central Asia, and it can be heard in parts of Central and North Africa and among blues and rock vocalists such as Howlin' Wolf and Captain Beefheart. Third, there is the "subtone" voice, which I think of as a kind of extension of the throat voice, but with prominent, and downright unmissable, sympathetic vibration of the false vocal folds and, in many singers, other surrounding tissues of the vocal tract. (For a more complete description of these voices and instructions for how to produce these voices, see my previous post).
When you have learned to do the voices, work on moving smoothly from one voice to the next. Begin with your natural singing voice, on a comfortable, mid-to-low pitch, and increase tension until you move into the "throat voice, and then return to your natural voice. Also, move from the natural voice, to the throat voice, to the "subtone" voice, and then return again, breathing as needed. Remember the exercise is to attempt to make smooth transitions, but the result may be more of a turning on and off of these vocal sounds.
6) To produce the lip trembling effect, purse the lips to the point of muscular exhaustion until they ripple subconsciously. I receive many questions about the style which I have listed on the video as "khoomei borbangnadyyr", and I have learned from a few viewers that this may be actually named "byrlang." Like many great things in life, the tremelo effect of the lips is not done consciously. I cannot speak for others, but when I do it, I purse my lips, pushing them forward, and then open them gradually and slightly to find the ideal size of the aperture. Sustaining this position, I feel the muscles surrounding the embouchre begin to fatigue. With only a little time, the lips begin to shake uncontrollably. I love this technique because it illustrates a great truth that there is strength and purpose in weakness. The more you practice the lip tremelo, however, the stronger you make the muscles, and so the more difficult it becomes to fatigue them. But no matter how beefy your chops get, there is always a "sweet spot" somewhere in the positions of the pucker and aperture that is weak enough to surrender to your "hidden will."
7) Sing outside. Explaining this one isn't easy, nor is it really necessary. The natural environment is composed of powerful archetypal symbols that positively affect the human organism. The forms of nature--shapes, sounds, smells, textures, tastes--instill quietude and awareness that is conducive to overtone singing. I have a theory as to why, but I don't want to write about it write now. You may find that the most pristine outdoor locations--edenic sanctuaries in your own backyard--inspire you to sing in this way. Moreover, many overtone-singing traditions have strong ties to the natural landscape and its myriad creatures.
8) When you sing a sound you like, don't celebrate too soon; instead, take a moment to reflect on and remember the sensation of how it felt. Finally getting it can leave you so excited that you neglect to notice how it feels when you perform correctly (by correctly, I mean the way you want it to sound). Rather than going to show a friend, setting up the recording equipment, or running to your dad's house to sonically heal his eczema, relax and observe your physical sensations and mental attitude that led to the successful performance.
9) Move through the overtone series as slowly as possible. Beginners often try to move up and down the overtone series too quickly, racing about and making articulatory movements too gross for stability. When you find three, two, or even one overtone(s) you can sustain with some clarity, stay there....enjoy that sound. Moving slowly is not only more difficult than moving quickly, but so too one can develop more control and usually derive more musical pleasure and meaning from singing within a limited range of the series; at least, at first.
Aside from these nine simple suggestions, I can offer no more tips to mastery of overtone singing in all styles. It is impossible for, if not detrimental to, a student to receive a handful of universal, fix-all tips. A teacher must hear and see a student to make a proper assessment of a student's ability and potential. There are too many variations on physiology and methods to help anyone without virtual or actual contact.
Finally, to reiterate, skills can be discovered and perfected all alone in a room. You don't need a cave, or a mountain top, an emaciated guru, or a trip to "exotic" locations to learn to overtone sing. Though I believe one can come to know the world from one spot on the floor in the house one was born in, there might be some truth to authenticating some styles by visiting specific locations on the planet. I just don't know for certain. But do beware of authenticity, as most of the time, whenever authenticity arises in a discussion, there is a either a personal or cultural ego fighting for superiority over another. Oh, and money--authenticity debates and money seem to go together like rich kids and belted, khaki shorts.
"Ours is better than yours"---what an asinine statement. If such debates arise around you, get away from those people and go to nature, an entity which has no need to justify its identify, and so it lives on and on.