The experience of your voice shaking or feeling unsteady while singing is a common concern that vocalists often seek to understand. This instability, which can range from a slight quiver to a pronounced wavering, signals a disruption in the finely tuned process of voice production. The causes are varied, spanning from simple technical flaws to more complex underlying issues.
What is Vocal Tremor and Instability
The general term for uncontrolled shaking in the voice is vocal instability, but the specific technical terminology depends on the nature of the oscillation. If the shaking is rapid and narrow, often caused by excessive tension in the larynx, it is referred to as an uncontrolled tremolo. This instability results from the vocal folds being held too tightly or with too much pressure.
A different form of instability, characterized by a slow, wide fluctuation in pitch and volume, is often called a vocal wobble. This wobble typically indicates a lack of consistent control, which allows the vocal folds to become slack and oscillate broadly. Both tremolo and wobble are considered undesirable because they show an imbalance in the singer’s control over the air stream and laryngeal muscles. The more serious, persistent, and involuntary form of vocal shaking is formally known as vocal tremor.
Mechanical Factors Affecting Vocal Stability
The most frequent cause of vocal instability in singers relates directly to the physical mechanics of voice production, primarily involving breath support and laryngeal muscle tension. Singing requires a steady, controlled stream of air, which is regulated by the engagement of the core respiratory muscles. Insufficient breath management means the air pressure below the vocal folds, known as subglottic pressure, is inconsistent.
This inconsistency allows the vocal folds to become slack, or under-resisted, leading to the wide, slow pitch oscillation characteristic of a wobble. The slackness causes the vocal folds to vibrate with too little resistance from the supporting breath, resulting in an unstable sound. Proper breath management is about maintaining a consistent, controlled exhalation that holds the folds in a stable position.
Conversely, some instability stems from improper laryngeal muscle tension, often as a compensatory effort for poor breath support. When a singer attempts to use muscles in the throat and neck to squeeze or force the sound, this tension can create a rapid, narrow oscillation, or tremolo. This excessive muscle effort, known as hyper-adduction, overworks the laryngeal muscles.
The vocal folds are then subjected to irregular, jerky movements because two sets of muscles—the ones closing the folds and the ones trying to control pitch—are pulling against each other inefficiently. This muscular imbalance prevents the folds from vibrating freely and consistently. Additionally, poor posture can restrict the movement of the diaphragm and supporting muscles, hindering the ability to generate stable subglottic pressure.
Distinguishing Tremor from Controlled Vocal Vibrato
The key distinction between uncontrolled shaking and a healthy voice effect lies in its intentionality and regularity. Controlled vocal vibrato is a natural, rhythmic oscillation in pitch and loudness that is a byproduct of a balanced, free, and healthy vocal mechanism. It is a volitional effect that a skilled singer can turn on or off at will.
This desirable vibrato typically occurs at a rate between 5 to 7 cycles per second (Hertz) and is a sign of freedom from excessive tension. When the vocal system is in balance, the interplay between the breath and the laryngeal muscles naturally creates this oscillation. It adds warmth and richness to the tone without compromising the stability of the central pitch.
In contrast, vocal tremor is entirely involuntary and is a sign of either muscular mismanagement or an underlying physical issue. While both tremor and vibrato involve oscillatory movement, the tremor is often irregular, too fast (above 7 Hz), or too slow (below 4 Hz) and cannot be consciously suppressed. A singer experiencing a technical wobble or tremolo is still struggling with a form of involuntary instability that they cannot control or smooth out.
When Shaking Indicates a Deeper Issue
While most vocal instability is linked to technique, persistent, involuntary shaking can sometimes indicate a deeper, non-technical issue. One of the most common neurological causes is Essential Vocal Tremor, which causes a rhythmic quivering of the voice due to involuntary contractions in the muscles of the larynx and surrounding structures. This is a movement disorder that is usually present during speaking, not just singing, and is often an isolated condition.
Another related neurological disorder is Spasmodic Dysphonia, where involuntary spasms in the vocal fold muscles cause the voice to sound strained, tight, or breathy, and may include a secondary tremor. Less severe but common is a situational tremor brought on by performance anxiety or extreme fatigue. This is not a neurological disorder but a temporary tremor caused by a surge of adrenaline and muscle tension in stressful moments.
If vocal instability is rhythmic, persistent across all vocal tasks, and cannot be corrected by improving singing technique, it warrants consultation with a medical specialist such as a laryngologist or a neurologist. These professionals can use tools like videostroboscopy to observe the vocal fold movement and determine if the shaking is a functional issue or a neurogenic problem requiring medical management.