Resonance
Your Body as a Resonating Chamber
You've probably been told that your instrument is not just an object for manipulation by the fingers, but an extension of the human voice. But what does this mean? Well, your body is the resonating chamber. When you produce a sound on your instrument, the sound travels inward as well as out, just as on a violin the sound comes from the body of the instrument and not the strings alone.
Personally, I imagine it as a pool of still water, and you throw a stone in, creating ripples, vibrations, on the surface of the water. If your water was in a different shaped pool, say, violin shape, the ripples are going to do different things, bouncing off certain edges before others, colliding with each other... That's why a violin sounds the way it does.
The beauty of a wind instrument is that we can (and should) consciously and deliberately change the shape of the resonating chamber while we play, just like when we talk or sing, since the voice is not limited to the movement of the vocal cords alone, but involves a symphony of internal processes that shape the sound. This is why the flute is an extension not only of the voice, but of the body.
On developing a sound, listen a lot to people who play with the type of sound you want to go for.
What is a Resonator?
Everything that possesses the properties of mass and compliance acts as a resonator. An air volume possesses both these properties: air has mass (even though it doesn't weigh much), and it can be compressed, meaning it strives to resume its original volume (compliance). For this reason, the air enclosed in the vocal tract acts as a resonator.
Characteristics of Resonators
Decay: If you hit a resonator, sound within it decays slowly. It will resound, and the resulting sound will not fade away immediately. In a piano string (an extreme type of resonator), the decay is extremely slow. In the vocal tract, the decay is much more rapid. You can hear this by flicking your neck above the larynx with a finger while the glottis is kept closed and the mouth is kept open - it sounds as if you had hit an empty bottle or tin.
Selective Transmission: A resonator allows sounds to pass through it under certain conditions depending on the frequency of the sound. Sounds having certain frequencies pass through the resonator very easily, so they are radiated with high amplitude. These specially transmitted frequencies that fit the resonator optimally are called resonance frequencies or, in the human vocal tract, formant frequencies.
Damping: If a tone with a frequency different from a formant frequency passes through the resonator, the tone will be transmitted with reduced amplitude, the resonator damps it.
Understanding Formants
What Are Formants?
Formants are the resonance frequencies of your vocal tract. When you play or sing, you're generating a sound source (from vibrating reeds, lips, or vocal folds) that contains many harmonic frequencies. This source spectrum passes through your vocal tract, which acts as a filter. The vocal tract resonates at certain frequencies (formants) and amplifies those frequencies in the final sound that emerges.
Most resonators possess multiple resonance frequencies. In the vocal tract, the four or five lowest formants are most relevant:
First and Second Formants (F1 & F2): Determine most of the vowel colour
Third, Fourth, and Fifth Formants (F3, F4, F5): Critical for voice timbre and personal sound quality
How Formants Shape Sound
The spectrum you hear is determined by which partials of your sound source lie close to formant frequencies. Partials lying closest to a formant frequency are "helped" on their way out, appearing stronger in the radiated sound than partials lying further from formant frequencies.
This is crucial: Vowel quality and a good deal of voice colour are determined by the formant frequencies. Since formant frequencies depend on the shape of the vocal tract, vowel quality and voice colour ultimately depend on the shape of the vocal tract.
Formant Frequency Ranges
In male adults, approximate formant ranges are:
F1: 250-1000 Hz (most variable with jaw opening)
F2: 600-2500 Hz (most sensitive to tongue position)
F3: 1700-3500 Hz (sensitive to tongue tip position and cavity behind incisors)
F4 & F5: Less mobile, more dependent on vocal tract length and larynx tube shape
Anatomy and Function of the Larynx
The larynx, also known as the voice box, is a cartilaginous structure located in the middle of the neck near the Adam's apple. It acts as both a gateway to the lungs and a key player in phonation.
Key Components and Functions
Vocal Cords: Housed within the larynx, these folds vibrate to shape the air stream. The vocal folds are approximately 3mm long in newborns and grow to about 9-15mm in adult females and 15-20mm in adult males.
Larynx Tube: A narrow, short tube about one or two centimetres long, inserted into the bottom part of the pharynx. This tube is crucial for resonance - its dimensions strongly affect the fourth formant frequency.
Laryngeal Ventricle: A small cavity between the vocal folds and the ventricular folds. When appropriately expanded, it can significantly lower the fourth formant frequency.
Piriform Sinuses: Pear-shaped cavities on the right and left of the larynx tube at the bottom of the pharynx. These expand when the larynx is lowered, affecting resonance characteristics.
Proper Positioning of the Larynx
Maintain natural head positioning relative to the shoulders. Avoid pushing the head forward or tilting it down
Bring the instrument to you rather than reaching or contorting the neck
Ensure that the throat remains free of tension, focusing tension only in the ribs and diaphragm for breath support
These adjustments help the larynx remain agile and versatile, contributing to efficient air modulation and tone production.
The Mouth Cavity as Your Personal Concert Hall
In wind playing, the mouth cavity plays a critical role in shaping and colouring the sound. The air stream, embouchure, and throat must work together seamlessly to create a resonant and expressive tone.
The Dynamic Oral Cavity
The oral cavity includes the jaw, tongue, and throat. These elements play roles in shaping the sound during playing. The shape and function of the oral cavity constantly change throughout a piece. Just as the oral cavity shifts naturally during speech or singing, it adjusts in real time during playing, shaping the tone and enabling expressive sound.
Controlling Formant Frequencies Through Articulation
The Jaw: Jaw opening is particularly decisive for the first formant frequency (F1). An increase in jaw opening tends to raise F1. Almost all formants are also raised by widening the lip opening.
The Tongue:
When the tongue constricts the anterior part of the vocal tract (palatal articulation), F2 is raised
When the tongue constricts the velar region, F2 is low
When the tongue constricts the pharynx, F2 is lowered to a lesser degree
F2 reaches its lowest value if the tongue constricts the velar region while the lips are protruded
F3 is particularly sensitive to the tongue tip and the size of the cavity immediately behind the incisors - if this cavity is large, F3 tends to be low
The Lips:
Rounding and protrusion lengthen the vocal tract
Almost all formants are lowered by narrowing the lip opening
Almost all formants are lowered by lengthening the vocal tract
The Velum: When raised, it shuts the connection between vocal and nasal tracts; when lowered, it opens passage to the nasal cavities, dramatically affecting resonance.
Vertical Larynx Position:
Lowering the larynx lengthens the vocal tract, lowering all formant frequencies
Lowering the larynx expands the bottom part of the pharynx
When the pharynx cross-sectional area is more than six times the larynx tube opening area, the fourth formant becomes highly dependent on larynx tube dimensions
A lowered larynx can lower F4 from a typical 3.5 kHz down to 2.8 kHz in adult males
Area Function
The vocal tract shape can be described by an area function - a curve where the horizontal axis represents distance to the glottis and the vertical axis represents cross-sectional area at that point. The area function determines formant frequencies:
Each vowel sound is associated with a specific articulatory profile
This produces a specific area function
Which in turn gives a specific combination of formant frequencies
The two lowest formant frequencies are most important for vowel quality
The Singer's Formant: A Resonance Phenomenon
One of the most important resonance discoveries in vocal research is the singer's formant - a peak in the spectrum around 2500-3000 Hz in male voices (slightly higher in females) that allows singers to be heard over orchestras.
What Creates the Singer's Formant?
The singer's formant is NOT an extra formant but a clustering of the third, fourth, and fifth formants in a narrow frequency band. This clustering creates a strong spectral peak that:
Corresponds to a frequency region where orchestral sound is relatively weak
Matches a frequency region where the ear is particularly sensitive
Can add 10-20 dB or more to the sound level in this crucial frequency range
How to Achieve the Clustering
The singer's formant requires specific adjustments:
Lowering the larynx: This lengthens the pharynx, which is particularly important for lowering F2 in front vowels
Widening the bottom of the pharynx: A lowered larynx widens the piriform sinuses and bottom pharynx
Critical dimension ratio: The pharynx cross-sectional area at the level of the larynx tube opening must be more than six times the area of that opening
Laryngeal ventricle expansion: If the lowering of the larynx expands the laryngeal ventricle, F4 can be lowered from 3.5 kHz down to 2.8 kHz
When these conditions are met, F3, F4, and F5 cluster together in the 2-3 kHz region, creating the singer's formant peak.
Pedagogical Applications
Many traditional voice teaching methods unknowingly target this resonance:
"Take your breath as in a yawn" → lowers larynx, widens pharynx
"Smell a rose" → lowers larynx during inhalation
"Sing as if you were crying" → often involves lowering larynx and widening pharynx
"Sensation of inhalation while singing" → maintains lowered larynx position
Application for Instrumentalists
While you can't manipulate your larynx as freely while maintaining embouchure, understanding these principles helps you:
Maintain an open, lowered throat position
Avoid constriction in the pharynx that would eliminate beneficial resonances
Create maximum space for resonance even while forming embouchure
Understand why certain vowel shapes inside your mouth produce different tone colors
Vocal Tract Length and Resonance
Length Effects on Formants
The fundamental rule: The longer the vocal tract, the lower the formant frequencies, other things being equal.
Typical vocal tract lengths:
Adult males: 17-20 cm
Adult females: shorter than males
Children: 7-10 cm (varies greatly with age)
This explains why children sound different from adults even when producing the same vowel - their formant frequencies are approximately 20% higher due to shorter vocal tracts.
Modifying Vocal Tract Length
You can actively modify effective vocal tract length:
Lengthening strategies:
Lowering the larynx
Protruding/rounding the lips
Both together have cumulative effect
Shortening strategies:
Raising the larynx
Retracting mouth corners (smiling)
Practical experiment: Pronounce the vowel /i/ (as in "beat") with normal lips, then with protruded lips. With protruded lips, the vowel changes toward /u/ (as in French "tu"). This is due to the lowering of all formants from the increased vocal tract length.
Body Vibrations and Resonance Perception
How You Sense Resonance
When you play or sing, you experience your sound very differently from how listeners hear it. This is because you perceive sound through three pathways:
Air conduction: Sound traveling through the air to your ears (what listeners hear)
Bone conduction: Vibrations conducted through skull bones directly to inner ear
Body vibrations: Tactile sensations of vibration in various body structures
Vibration Patterns in the Body
Research using holographic techniques shows that during phonation, various body structures vibrate:
Chest wall: Vibrates strongly, especially at lower frequencies
Neck and throat: Strong vibrations that vary with pitch and vowel
Facial structures: Including forehead, nasal bones, teeth
These vibrations are NOT responsible for the sound that listeners hear (chest resonance doesn't make sound), but they provide crucial proprioceptive feedback that helps you control your instrument/voice.
"Placement" and Resonance Sensations
Terms like "placement in the mask," "head resonance," and "chest resonance" refer primarily to where you feel vibrations, not where sound is actually resonating or being amplified. These sensations are valuable for:
Developing consistent technique
Monitoring changes in your production
Maintaining awareness of your physical state
However, these sensations can be misleading about the actual acoustic output. What feels very resonant to you may not sound particularly resonant to listeners, and vice versa.
Practical Resonance Experiments
Exploration Exercises
Vowel Sounds: Sing different vowel sounds (e.g., "ah," "ee," "oo") while playing to observe how the throat and jaw respond. Pay attention to:
How each vowel affects your sense of resonance
Where you feel vibrations for each vowel
How tone colour changes with different vowel shapes
Which vowels make playing easier or harder
Air Temperature: Alternate between blowing "hot" and "cold" air. Notice:
The difference in air pressure and tone quality
Changes in the shape of your oral cavity
How the feeling of air speed differs
Impact on the resonance you feel and hear
Embouchure Experimentation: Adjust the tension in your upper lip, the pressure on the ridge under your nose, flaring your nostrils, and the pressure between your lips. Observe how each affects the resonant space behind the embouchure.
Tension Awareness: Create tension deliberately - close the throat, stretch the jaw, and then relax. Experiment to find a deep, rich sound without strain. Notice:
How tension affects the resonant spaces
Which tensions completely block good resonance
The minimal tension needed for tone production
Larynx Height Awareness: While sustaining a tone, deliberately raise and lower your larynx (swallowing motion vs. yawning motion). Notice:
How this affects tone colour
Changes in the resonance you feel
Impact on ease of production
Which position feels most open
Tongue Position Mapping: Sustain a tone and move your tongue to different positions (without breaking the sound):
Forward/back
Arched/flattened
Tip up/down Notice how each position affects both the tone you hear and the vibrations you feel.
Understanding Harmonics and Overtones in Resonance
The Source-Filter Model
Think of sound production in two stages:
The Source: Your embouchure/reed/vocal folds generate a complex tone containing many harmonics (the harmonic series: fundamental, 2x fundamental, 3x fundamental, etc.)
The Filter: Your vocal tract resonances (formants) selectively amplify or dampen these harmonics based on how close each harmonic is to a formant frequency
The radiated sound = source spectrum × filter characteristics
Harmonic Series and Partials
When you produce a tone with fundamental frequency f:
1st partial (fundamental): frequency = f
2nd partial: frequency = 2f
3rd partial: frequency = 3f
4th partial: frequency = 4f
And so on...
All partials sound simultaneously, creating the complex tone you hear.
How Formants Emphasise Harmonics
Imagine playing A4 (440 Hz fundamental):
Harmonics occur at: 440, 880, 1320, 1760, 2200, 2640, 3080 Hz...
If your F1 is at 750 Hz, the 880 Hz harmonic (2nd partial) will be strongly amplified
If your F2 is at 1300 Hz, the 1320 Hz harmonic (3rd partial) will be strongly amplified
If your F3 is at 2600 Hz, the 2640 Hz harmonic (6th partial) will be strongly amplified
Result: Even though the source might have similar amplitude for all harmonics, the radiated sound will have peaks at the harmonics closest to formant frequencies.
Manipulating Overtones for Tone Color
"Yellow" (Hollow, Fundamental-Rich) Tones:
Fundamental is emphasised relative to overtones
Created when F1 is close to fundamental frequency
Often requires lower jaw position, more open oral cavity
Characteristic of darker, warmer, more "covered" sounds
"Purple" (Harmonic-Rich) Tones:
Upper harmonics are emphasised relative to fundamental
Created when formants are positioned to amplify higher partials
Often requires different tongue positions and oral cavity shapes
Characteristic of brighter, more brilliant, more "forward" sounds
Practical application: You can shift between these colours by:
Adjusting jaw opening (affects F1)
Changing tongue position (affects F2 and F3)
Modifying lip opening and rounding (affects all formants)
Altering larynx height (affects all formants, especially F4)
Resonance Strategies for Different Registers
Lower Register
In lower register:
Formants are naturally spaced well for clear vowel definition
First formant is typically well above the fundamental frequency
Focus on maintaining open pharynx for rich harmonic spectrum
Singer's formant (for instrumentalists: equivalent focused resonance) easily achieved with lowered larynx
Middle Register
In middle register:
Balance becomes crucial as fundamental frequency rises
May need to adjust formants to maintain optimal spacing
As fundamental approaches F1, consider whether to raise F1 or accept the increased amplitude of fundamental
Most versatile register for resonance manipulation
Upper Register
In upper register (particularly relevant for flute, piccolo, soprano singers):
Fundamental frequency may exceed normal F1 frequency
Pitch-dependent formant tuning becomes necessary
Jaw opening often increases with rising pitch to keep F1 near or above fundamental
Vowel definition becomes more difficult - formant frequencies start to converge
For very high pitches, conventional vowel articulation must be abandoned in favour of maximising resonance efficiency
Critical principle for high register: When fundamental frequency rises above the normal F1 frequency for a vowel, you gain loudness and projection by raising F1 to match or slightly exceed the fundamental. This is achieved primarily through increased jaw opening, but also through adjusting tongue position and vocal tract length.
Developing Resonant Playing
Systematic Practice Approaches
Record and Analyse:
Record long tones across your entire range
Listen for consistency of tone colour
Identify register breaks or resonance gaps
Note which areas feel most resonant vs. sound most resonant
Track changes over time
Formant Awareness Practice:
Sustain a pitch and systematically change oral cavity shape
For each shape, note: tone colour, perceived loudness, ease of production, vibration sensations
Develop your personal "resonance map" for different pitches
Long Tones with Variables: Practice sustaining notes while systematically varying:
Jaw opening (small increments)
Tongue height and position
Lip rounding/spreading
Pharynx width (thinking "yawn" vs. neutral)
Larynx height (if possible while maintaining embouchure)
Note which combinations produce:
Maximum resonance sensation
Maximum projected sound
Best tone color
Easiest production
Throat Tuning Practice:
Sing the pitch you're playing (or sing along while playing)
Try to match the resonance sensation in your throat between singing and playing
This helps align your vocal tract resonances with your pitch
Gradually internalise this feeling without needing to sing
Vowel Exploration: While playing a sustained pitch, slowly morph through vowel shapes:
/u/ → /o/ → /ɔ/ → /a/ → /æ/ → /e/ → /i/
Notice which vowels enhance which partials
Discover which vowel shapes work best for different timbral goals
Develop flexibility in quickly accessing different resonance configurations
Building Proprioceptive Awareness
The most skilled players develop acute awareness of internal sensations that correlate with good resonance:
Catalogue sensations: For each successful, resonant tone, note:
Throat feeling (open, spacious, relaxed)
Tongue position and tension
Jaw position and tension
Soft palate position
Pharynx width sensation
Where you feel vibrations most strongly
Develop "home base" positions: Find neutral, efficient positions for major registers that you can return to as reference points
Practice rapid adjustments: Work on quickly finding optimal resonance when jumping between registers or dynamic levels
Auditory-proprioceptive linking: Strengthen the connection between the sound you hear and the feelings that produce it
Advanced Resonance Concepts
Resonance and Vocal Effort
Research shows that perceived "vocal effort" or intensity of playing relates strongly to resonance efficiency:
Efficient resonance: When formants are optimally positioned relative to the harmonic series, you can produce loud, projecting sound with moderate physical effort.
Inefficient resonance: When formants are poorly positioned, you must work much harder physically to achieve the same acoustic output.
This explains why some players seem to produce huge sounds "effortlessly" - they've learned to optimise their resonance rather than simply blowing harder.
The Resonance-Articulation Balance
Every resonance adjustment affects articulation, and vice versa:
Opening the jaw for better F1 matching affects embouchure
Lowering the larynx for richer resonance affects breath management
Tongue positioning for ideal F2 affects the airstream shape
Skilled playing requires finding positions that optimise both resonance AND the technical requirements of your instrument.
Resonance and Musical Expression
Beyond technical efficiency, resonance control is a primary tool for musical expression:
Timbral variety: Different formant configurations = different colours = different emotional qualities
Dynamic shading: Resonance adjustments can create the illusion of dynamic change even with constant air pressure
Phrase shaping: Subtle resonance shifts throughout a phrase add life and direction
Textural contrast: Alternating between fundamental-rich and harmonic-rich resonance creates variety
Conclusion: The Resonant Instrument
Your instrument truly is an extension of your voice. By understanding the mechanics of resonance - how formants shape spectra, how articulation controls formants, how body structures provide feedback, and how the source-filter model explains tone production - you gain powerful tools for developing your sound.
Key principles to remember:
Your vocal tract is a filter that shapes the sound from your source (embouchure/reed/vocal folds)
Formant frequencies are your primary tool for controlling tone colour and projection
Articulator positions determine formant frequencies - jaw, tongue, lips, velum, and larynx height all matter
Optimal resonance requires matching formants to the harmonic series of your fundamental frequency
The singer's formant principle (clustering F3, F4, F5) applies to creating focused, projecting tone
Your proprioceptive sensations guide you but don't directly correlate with acoustic output
Resonance efficiency allows you to produce maximum sound with minimum effort
Practice with awareness, experiment systematically, and remember that developing optimal resonance is a never-ending refinement process. Your body is your primary instrument, whether you're singing or playing.