I begin with a disclaimer. This article is not about the voix couverte, a musical and technical “lifestyle choice” which is better understood by voice teachers and acoustic scientists than me.
As an otolaryngologist, my concern is rather with patients—singers—who are unable to bring the voice forward even if they want to. “Covering” in this sense refers to a constriction or occlusion of the pharyngeal resonance chamber at the level of the oropharynx. The resulting voice is in the back of the throat, lacks clarity and brightness, and has a booming quality and underpowered consonants. What are some causes—and what may be some solutions?
Probably the most common cause for this sort of physical “covering” is the tongue. Much of the tongue’s musculature arises from the hyoid bone. The hyoid, in turn, is attached to the larynx. In untrained singers, the tongue-hyoid-larynx complex naturally moves as a unit. To lower the larynx, then, the easiest thing to do is to push the tongue back, dropping both the hyoid and the larynx. Easy, but incorrect: this maneuver not only pushes the tongue back into the oropharyngeal inlet, but often also balls it up, increasing the occluding tongue mass at a critical location.
Another tongue issue is simply the inability to drop the tongue while raising the soft palate. On examining patients, I can always tell the trained singer—as I place the tongue depressor into the mouth, the back of the tongue sinks down, opening the oropharyngeal inlet. Untrained and non-singers have a large hump at the back of the tongue—its normal appearance.
The treatment for this sort of covering is in the hands of the voice teacher. As with so much in singing, the student needs to learn to gain conscious control of reflexive movements and to separately activate some muscles while relaxing others. No need for a doctor here, just for good teaching and lots of practice. While eliminating occlusion by the tongue is usually a matter of training, a minority of patients simply has a large tongue which is difficult to lower, trained or not.
A harmless phenomenon that I have also seen in baritones with aspirations of bass-hood is that they push their speaking voice down and back to create a sound that is darker and lower than their natural speaking pitch should be. These are well trained singers, and such vocal behavior is a matter of personal choice, not lack of technique.
More in the medical sphere are singers with a constant constriction or partial occlusion at the oropharyngeal inlet. Some patients have massive tonsils that narrow the opening. The tonsils may not be infected or otherwise troublesome, just very big. Keep in mind that such tonsils not only narrow the opening from either side, but also project down into the hypopharynx, causing further obstruction. Such tonsils not only make it difficult to bring the voice forward but to also change the resonant characteristics of the hypopharynx. In truly extreme instances, the patient even speaks with a muffled, almost “hot potato” voice. The voice is also dark, because the resonance normally activated in the mouth and the articulators is not accessed.
Not uncommonly, these patients also snore at night. The muscles of the throat relax during sleep, and tonsils get sucked into the airway with each breath. In truly extreme cases, sleep apnea may develop. Many of these patients learn to sleep on their side or their belly, to partially move the tonsils out of the way. Over the years, I have had a number of such patients referred to me for tonsillectomy. Their voice teachers have also suggested (and I have no reason to disagree) that with large, heavy tonsils singers may even have difficulty lifting the palate. After tonsillectomy, the phenomenon disappears—the voice gains clarity and moves forward with more brightness and better projection. The theoretical concern about postoperative scarring and tethering of the palate is just that—theoretical; in practice, this should not happen if the procedure is done carefully.
A less obvious cause for narrowing of the oropharyngeal isthmus is enlarged lingual tonsils. This is tonsil tissue that grows across the back of the tongue, “just over the hump” as you look into the mouth. Enlargement often occurs if a patient had their tonsils removed at an early age and then continued to have throat infections. Lingual tonsils can be seen with a mirror held over the top of the tongue. When truly massive, they can even push back on the epiglottis. Although it is rare for lingual tonsils to cover the voice, they should be kept in mind if a singer has difficulty flattening the back of the tongue and achieving an open sound.
Adenoids are yet another collection of tonsil-like tissue, this time in the nasopharynx. Significant obstruction here results not only in snoring and mouth breathing but also a denasalized voice, with diminished nasal resonance and a sense that the voice is stuck farther back than it should be. Fortunately, adenoids usually shrink to an insignificant size after puberty. Rarely, however, they may persist, especially when a patient has ongoing inhalant allergies.
The acoustic effects of thick and lax pharyngeal tissue in general should be considered in singers who are obese. While not a clear cause for muffling the voice, this phenomenon plays a role in possible obstructive sleep apnea—as the patient breathes in, the flow of air creates a suction effect on the pharyngeal walls with partial collapse and, rarely, significant occlusion.
As we look to bring the voice forward, a final area to consider is the nose. Even in cases where the oropharynx is open, the tongue is down, and the palate is up, a singer may have difficulty bringing the voice into the mask. This may be due to nasal obstruction. I am told that resonance “in the mask” really originates in the hard palate, which forms both the floor of the nose and the maxillary sinuses. A deviated septum or enlarged turbinates can decrease the nasal cavities and change their resonant characteristics. Medical or surgical treatment in such cases not only addresses the non-vocal complaints on nasal obstruction or snoring, but can also improve the proprioceptive and acoustic characteristics of the voice.
