If you have a good solid vocal technique, and you know that you can rely on your voice to do what you expect it to do, congratulations! Not everyone gets there.
If you sing in a specific style, whether it be classical, rock, jazz, country, or another one, and you sing material that is more or less in a certain “groove” or “fach”, you may not go very far away from your comfortable home base most of the time and your technical “chops” likely will remain steady and reliable as well.
But if you are out there singing, unless you write all your own tunes and never write anything that’s vocally or musically challenging, sooner or later you will encounter something that shakes up your technique and starts to pull at your vocal behavior. It wouldn’t necessarily be something that causes you vocal health issues (although it could lead to them over an extended period), but it could make your voice feel “not quite right”, even though you can certainly still sing and most people would hear you as being “just fine”.
What’s to do, then? Should you avoid material that “messes up your machine”? Should you not do new or challenging repertoire? Should you try to find a way to do only what’s most comfortable all the time? If there is a way to do that, I would be happy for you to contact me and tell me what it is because I would be happy to know. It could be, though, that in the real world of performing there is no such place or state of being and you are going to have to contend with this issue if you want to have a continuing, valid and successful career.
If you are really in touch with your heart when you sing, good music will pull on it and ask you to go where it wants you to go. If you follow your heart (and, really, you must) then you have no choice but to let yourself sing the music the way you feel the music should go and find a way to marry it’s call with the parameters of your vocal expressiveness. Not to do this is to live in a protected state and no real artist wants to do that for very long. We are by nature a restless lot, always looking to “what’s next” in our exploration of our art. Finding the path is a daily discovery — tricky, arduous, fatiguing but exhilarating when we experience the satisfaction of creating what we had hoped we would.
If you do a song that is powerful, heavy, dramatic and long, you will find that it gives you vocal strength, a solid delivery, stamina of breath and phrasing, and a sense of rootedness in your body. You might also find that it makes your voice heavier, sluggish, less responsive, less willing to sing softly or smoothly, and less happy to move around quickly. The reverse is also true. If you sing something that is light-hearted, delicate, intimate or short, you will find that it gives you a sense of freedom and ease, a feeling that your voice moves like quick silver, and a delight in singing softly and in higher pitches. You could also discover that it gets harder to sing a full, rich sound, it gets harder to hang on to long loud phrases, especially in mid or lower pitch ranges, and that you seem to have a slightly less steady feeling in your body. If you sing music that goes all over — something that is high and low, loud and soft, rangey but with shorter segments mixed in here and there, and asks for a range of communications from happy to sad, angry to frightened, you will find that it expands your capacities to sing in many different ways and pushes the boundaries of what you can do past the limits you had become accustomed to. It can also take your voice apart, make it a chaotic mess, weaken the top, the bottom, or the middle, or even all of those places, effect your vibrato, your breath support and your ability to control both loud and soft phrases. It could also effect your mental state.
If you do not understand that about repertoire, and believe it or not, many people do not, you could incorrectly assume that it was you or your voice that was the issue. You could assume that you need to change your technique because what you had been doing was inadequate. You could decide that you should never ever sing things that are unfamiliar or difficult because they are dangerous. Any of those things could be true, of course. You could also just take responsibility for the fact that repertoire is going to pull you where it does and that you have to re-group after you have done something new to get back to home base. That’s just normal.
I once had a chance to ask a question of the great Mirella Freni about her career. I asked her how it was that she sang for so long, so well. Given that she started out singing “Susannah” and ended up with “Elizabeth” in Don Carlo, that’s a wide and long journey to make. She answered that she always followed a heavy role with a lighter one and never agreed to sing something until she had learned it and “put it in her voice” for quite some time to see if she felt she could safely manage it. Many other artists have done similar things. Leontyne Price sang Mozart alongside Verdi for most of her career. James Morris sang lyric roles alongside dramatic roles until he tackled his first Wagner.
Artists in CCM styles may not think this way, but they should. They should evaluate repertoire in terms of what it does to the voice and make adjustments accordingly, particularly after they are no longer doing that repertoire. The voice should always have a balanced “home” to return to, so that it, and you as the vocalist, do not get lost.
If you don’t have such a vocal home base, go get one. If you lost it, work to get it back. If you don’t understand what I’ve written here, ask yourself why not.