(Old school diagram above is bird's eye view of the box - if the bird were sitting in the back of your mouth.)
As performers, we sort of rely on our voice box a lot. And I mean a lot. As people we rely on our voice boxes a lot in general. But to performers, whose ultimate purpose is to convey stories or ideas, it's rather essential (unless you're a mime, but I'm not working to be a mime, sorry Marcel). An actor's two main tools to manipulate are the voice and the body. This is focusing on the voice.
If these muscles aren't trained properly or used in the correct way, there can be serious damage done to them, which is an actor's nightmare. Losing your voice the night before a show? Eek. Permanent damage from straining the muscles incorrectly? Even bigger eek. But it's almost impossible to avoid a sniffly little cold every so often, right?
That is where Eric Armstrong's article comes in - "TAKE CARE OF YOUR VOICE: Simple ways for actors and others to keep the instrument in shape."
"As with good health in general, a few simple precautions and adjustments of habit can make a big difference."
There isn't always a miracle fix for a sore throat on musical night, but if you start now and train your body and voice in a way that is correct and healthy, you can protect yourself from vocal injury in the future. And not just actors need proper voice care - just about everyone in theatre does. Directors, stage managers, producers, crew heads, front of house staff... anyone who needs to communicate effectively should be taking care of themselves so that they have their voice when they need it.
Don't overdo it.
Theatre isn't the only thing you do. Everybody knows this - we all have other interests that can be potentially taxing on our bodies. Fatigue of the voice and body can be very detrimental. If you're a tired person, you've got a tired body, a tired mind, and a tired voice. Don't scream at sporting events if you're in the process of preparing for a show. Try to scale back vocal use leading up to the show - if it's an intense vocal part, you're going to need everything you've got, so be conscious of what you're doing vocally. All parts of the body need to be working in sync with each other for a prime performance.
Center your breathing.
There are different schools of breathing techniques out there, but the general point of all of them is to make sure that you have enough air to perform what you need to. People, in general, breathe shallowly in everyday situations; they breathe from the upper part of their chest, so that their breaths come from beneath the shoulders, neck and breastbone. This is just fine for everyday speaking, but onstage it can strain the neck and throat. Diaphramatic breathing is a general term for it, and my vocal instructors have come up with some clever terms to help me understand the concepts behind proper breathing. "Possum breathing" is my personal favourite, since it helps to remove all reliance on that upper chest breathing. Breathing from your core, deep, fluid air flow that causes your whole abdomen and part of your thorax (anatomy!) to push outward - that's the sort of breathing that needs to be done. Kristen Linklater's book discusses this quite a bit, so I would invest in that. See the Starry Eyed Idiot box for tools regarding it. The voice and air should pour out, not be pushed. Proper training with your breathing will add power and tone to a voice, because it is not being forced at all. It's better for the voice box as well.
This one might seem obvious, and it really should be, because a simple little warm up can make a very big difference. Get into the habit of warming up. It tunes your instrument - just like runners would never fly into a 100 meter sprint without stretching first (the consequenses of that are terrible to imagine - shredded gastronemicus, anyone?), actors should never go into any sort of performance without warming up the voice. It's a delicate little system, and needs to be treated as such. Focus yourself mentally, get your body working with stretches, engage your diaphramatic breathing, vocalize lightly to tune up... find a routine that works for you.
Water fixes lots and lots of vocal issues. A well hydrated body keeps the vocal cords (and the rest of your body) functioning smoothly and lubricates the works without getting all mucousy and tempting you to clear your throat. Dehydrated bodies create mucous to try and lubricate the vocal cords, but it's not good for the voice, so keep yourself hydrated. Most Americans are chronically dehydrated (according to some cool scientific studies), so go fix that statistic. If you're not American, you should still go hydrate yourself. The best way to get enough water is to sip on it all day - carry a water bottle with you; you'll be more likely to drink it if you have it handy.
HANDY (but awkward) TIP! If you pee pale, you're hydrated. The more water you've got in your system, the more you'll piss out and the clearer your pee will be. When I was trying to cure my bronchitis before an audition last semester, I drank so much water that I literally peed clear. I'm sure you wanted to know that. It kept me hydrated and I had at least a little bit of a voice to audition with, which is better than none. Water. It works.
Take care of your throat.
Armstrong addresses three problems that can injure the throat and what to do about them. Clearing the throat, coughing, and heartburn. Yes, that's bad for the voice too, not just your craving for chili. I won't talk about heartburn since I don't have it, and the only advice he gives is to go see a doctor.
Clearing the throat - Don't do it! The itch you feel at the back of your throat can be caused by mucous in the throat and mouth (a side effect of dehydration and colds and any number of things), and the habit of clearing the throat is instinctual, sometimes. But the action of clearing the throat bangs the vocal folds together (see little grey diagram) and can injure them, and when you clear your throat it just makes more fluid to soothe it, which can make you want to clear it even more. Vicious cycle. It's a bad habit that a lot of people have, including myself, and you want to make efforts to not do it anymore. The Miss Piggy "uh-hum" is a safe alternative, a gentler version of the throat clearing action.
Coughing - Don't do it! Just kidding. You can't help coughing if you're sick or have irritated your throat somehow. It's dangerous though because it blasts open your vocal cords and strains them very badly. Medication that limits the urge to cough and treats the underlying cause is the best way to go, if you have a stubborn cough. Cough drops aren't necessarily good for a cough-roughened throat, either, though I have found that sometimes they are my saviours (see the post about my love affair with Elderberry Ricola). Some lozenges contain menthol that can irritate the vocal cords while cooling your throat. If you want to use cough drops, I'd go for Ricola, since they seem less harsh in the long run, though they do still contain menthol.
Treat your cold.
The advice I needed three weeks ago! This is the ailment that affects people's voices the most. In addition to the fun of runny noses and stuffed sinuses comes the swelling of the tissues in the throat. The swelling can lead to hoarseness, or even the loss of your voice. That's never good for an onstage situation, and I always panic when I get a cold, since I seem to get them every six months on the dot. Or three months, depending on the weather. Steaming your airway is the best way to deal with a cold, Armstrong writes. Boil a pot of water, and carefully breathe the steam as you cover your head and the pot with a towel (see picture so you don't boil your face off). Humidifiers in winter are a good way to keep the airways nice and hydrated and prevent colds. Steam, lots of rest, and limiting the use of the voice are the best ways to cure a cold and get back on your feet for a performance. The absolute best way to treat a cold, of course, is to not get one in the first place, so taking care of yourself and staying healthy is the absolute best option around.
Be smart with extremes.
Different situations require different uses of the voice - theatre takes place in lots of different areas, and if a play is outdoors or in a tiny black box, it will require a different set of vocal skills to manipulate the voice appropriately for each area. Cold, dry, dusty places are rough on the voice, as are noisy places, since they can make a performer push their voices too much just to be heard. No matter what situation you are in, and what sort of performance you are in, the rule of thumb for me is that "if it hurts, don't do it." Nothing you do to your voice should ever strain or cause pain. You can seriously hurt your instrument doing that.
However, there are times onstage when a character may need to scream, yell, cry, choke, cough, maybe even puke. Those extremes can be damaging, so it is important that there is proper vocal technique being taught that can prevent those extremes from injuring a performer. Losing your voice for good is not worth one badly placed shriek in one show.
All in all, take care of yourself and your voice - eat well, drink enough water, get enough sleep (tough for students, but it's worth a shot anyway, haha), and playing smart no matter what the circumstance. Take care of your voice - it's the only one you've got.
Another credit to Eric Armstrong for most of the information presented here. Subscribe to Dramatics magazine - it's worth it.