What is a register?
Unfortunately the subject of registers is one which suffers from wide differences of opinion, and even worse, wide variations in terminology. It is not even clear, at this point in voice science research, to what extent registers are a physical, as opposed to an acoustic phenomenon. The two appear to be inextricably linked.
A simple practical definition might be that a register is a part of the range of the voice which is characterised by a particular timbre (quality of sound). To give extreme examples, a low pitch in a loud, heavy timbre might be referred to as being in the ‘chest’ register. A high pitch in a lighter, softer sound might be regarded as in “head” register.
Manuel Garcia’s definition
Manuel Garcia defined a register as a series of homogeneous (sounding the same) sounds produced by one mechanism, as distinct from another series of sounds equally homogeneous, produced by a different mechanism. He was observing the vocal cords during phonation with the first laryngoscope, and by ‘mechanism’ he meant the configuration of the vocal cords. In other words, as a singer sang a scale the configuration of the cords would remain approximately the same up until a certain point, then alter visibly. When Garcia observed this, and at the same time heard a change in the tone quality of the sound, he concluded that he was hearing a change in register. This definition is still in use, and as useful as any in my view.
Why are registers important?
About the only thing that most teachers do agree upon is that register ‘breaks’, or audible transitions between registers, are undesirable. One of the chief objectives in developing the voice is to eliminate breaks and achieve a smooth consistent sound throughout the range. When a voice ‘cracks’, what we are hearing is an abrupt register change.
How do I handle registers?
In my teaching I try to keep this as simple as possible, unless I am working with people who are teachers themselves and need a detailed understanding.
William Vennard (in “Singing: The Mechanism and the Technic”) (6) proposed the concept of only two muscular mechanisms affecting registration, the heavy and the light. I think this is as useful a model as any.
The heavy mechanism is dominated by the activity of the vocalis muscles (in the vocal cords themselves). A sound produced principally by this mechanism would be referred to by some as ‘chest’ voice. The light mechanism is dominated by the activity of the crico-thyroid muscles, which cause the vocal cords to thin and stretch. A sound produced principally by this mechanism might be referred to as ‘head’ voice.
The point is that in good singing, both mechanisms should be in use (with the possible exception of high coloratura in the female voice, and the special case of the male alto, or countertenor singer). The balance between the two mechanisms determines the quality of sound, and the ease of production. In a skillful, singer the balance between the two mechanisms is constantly changing in response to the demands of pitch, vowel and dynamics, and this is called ‘dynamic’ registration. No two pitches are sung identically.
I concentrate on creating the conditions under which the voice can be permitted to make these continuous and subtle adjustments, eliminating breaks. Consistent support, or control of air pressure, is essential. A break can be caused by insufficient support, allowing an abrupt change to a lighter configuration, or by excessive support, sometimes called ‘pressing’. Correct phonation, resulting from a balance between muscular activity in the larynx, and air pressure beneath it, is also necessary. Finally, the resonance adjustment needs to be appropriate so that an excessive ‘load’ is not being placed on the instrument. When these conditions are met, the issue of registers ceases to be problematic.
Passaggio is an Italian term for a series of notes in which a transition is being made between registers. Or, in the terms used above, from an area of the voice in which the heavy mechanism tends to dominate, to an area in which the light mechanism tends to dominate.
The necessity for ‘dynamic’ (constantly changing) registration has given rise to some of the more interesting theories of registration, for example the concept that every note is a register, or conversely, that there is only one register, both perfectly logical ideas. Of course, from the point of view of a ‘one-register’ theorist, the phenomenon of a passaggio should not exist. However, especially with beginners, these passaggi are predictable points at which the singer is likely to experience difficulties.