Health, strength and independence of the registers: 

If chest and falsetto cannot be sung separately, as in a yodel, they may need some work to become more independent before working to combine them. 

Register separation is done by singing a robust chest voice in the lower range, up to E above middle C, then with soft and breathy falsetto tone above that. Both registers will be weaker at the bottoms of their respective ranges and louder at the top. Octave leaps are very useful. Let the voice yodel if it wants to! 

Any work to separate the registers should be considered transitional and not hammered away on ad nauseum for extended time frames. The reasons for this are:

• You can get bored if the process is too repetitive.
• You can also get overly-fascinated with these exercises. They can be quite enjoyable, but they aren’t singing! There are other skills that only singing will develop.
• Your voice can change rapidly with exercise. Working the chest voice and falsetto separately will emphasize the break, so it’s good to do some register blending as soon as you get a little independence. Once some separation is established, register independence can actually benefit from certain exercises that begin to coordinate them.
• The muscles within the larynx are small and tire easily. They also recover quickly, so if something isn’t working right now, give your voice a rest for five minutes and try it again.

Once you have a comfortably robust chest voice and a fairly free falsetto, you can easily start to coordinate them together in a way that encourages them to strengthen and balance each other flexibly throughout your range.

Train the ear to hear and sing vowels accurately:

Training your ear to hear and adjust the quality of your vowels is a top priority. The benefits of this are extensive and multifold. Chief among these is that consistent vowel quality means consistent resonance adjustment, which then becomes a stable context for solving register issues and developing dynamic registration.

When you are working on your own, without a teacher present to point out your vowel infractions, I recommend that you record your vocal exercises for immediate feedback. This practice can be very instructive, if a little disconcerting, because hearing yourself played back reveals all the flaws! Your smartphone probably has a voice recorder that works well for this.

Joining the registers:

If the singer has access to both registers and a reasonably good grasp of vowel purity, they can begin the work of blending the registers. The main exercises for blending are the Octave Leap and Mezza di Voce, described below.

A session might go something like this:

• Begin with simple musical patterns that work the registers separately. These will be short in range, within the comfortable range of each register. As mentioned, yodels can be very helpful.
• Move into octave sized patterns that allow the voice to break into falsetto-dominant sounds in the upper notes.

If the falsetto begins to take on a more “legitimate”, less breathy quality, you can begin to use octave leaps where the upper note keeps a connected head voice quality. Three things to ensure are:

• Don’t strain. Begin with a firm, comfortable loudness on the bottom note and let the volume reduce for the top note.
• Keep the breath flow going - too much is better than too little, and
• Keep the vowel the same on the top as it is on the bottom.

The voice may break off, wobble, or the vowel may distort. In that case, don’t go as high, but persist at the limit of your current ability to maintain the vowel and the connected tone. The muscles in the larynx are small and may tire easily, so if it starts to break off, it sometimes helps to rest the voice for a minute and begin anew.

It is important not to exert control at this point, but rather to allow the voice to find its own way into this new balance between the registers. The main things to concentrate on are the pitch, the reduced volume on the top note, maintaining the right amount of breath flow and the vowel quality.

It can be helpful to put some “H”s into the upper note of the octave. This re-articulation of the tone requires the vocal cords to snap back into place and might spontaneously result in a better register adjustment for that note, without sacrificing the vowel.

I believe this is when your vocal cords will begin to learn how to dampen their rear portions for the high notes. You’ll know you’re on the right track when the high notes become more effortless.

The Mezza di Voce: 

Once you have stabilized a head dominant register adjustment on some of your upper notes, you can begin to experiment with swelling and reducing the intensity there. You may only be able to go from mezzo piano to mezzo forte at first. It’s better not to try to progress too fast. You will have a sense of the glottis resisting the breath pressure, which is good, and we don’t want to overwhelm it. Be sure to keep the vowel quality.

This practice of increasing and decreasing the intensity on a note, called Mezza di Voce, is a dynamic shift of registers on one note. It further strengthens your voice’s ability to find the best possible balance between chest voice and head voice for any given combination of pitch and intensity. 

Rhythm:

Something Cornelius Ried emphasized is the use of rhythm in vocal exercises. If the student sings a series of musical figures, such as triad arpeggios ascending a semitone at a time, they will benefit if this is done in a predictable, rhythmic way. It helps the singer relax into the timing, which promotes a more natural, spontaneous response in the vocal organs. 

Rapid vocal patterns can be used in this way to encourage spontaneous and new responses from the voice. It’s almost like we have to surprise ourselves or, to use an old saying, “get out of our own way”.