See your own voice
iSing into the mic and watch your own voice wiggle — steady notes draw tidy waves, higher notes wiggle faster.
for teachers: waves · frequency · pitchOpen →
Think you cannot sing? Start with the big button. Nobody is listening, and pitch is a skill you can learn — and never sing cold: the daily warm-up takes four minutes.
one pair of vocal folds · the math & physics of singing
No strings, no keys, no valves — just air, a buzz, and a tube you can reshape. And yet the same math runs through it: your voice is a wave, your range is a ratio, and every vowel is a filter. Sing into it and find out.
the big idea, in plain words
Your voice is a wind instrument you carry around, and it has exactly three parts. Your lungs are the bellows that push the air. Two small folds of tissue in your larynx chop that air into a buzz — and how many times a second they slap shut is the pitch. Then the tube above them — throat, mouth, tongue, lips, nose — reshapes that buzz into a vowel. Power, source, filter. That is the whole instrument.
plate vii · the voice, cut away
resting
Green is moving air and moving sound. Press take a breath and watch the dome of the diaphragm flatten and drop as the lungs fill — then rise slowly back up as the note uses the air.
1 · the power
Your diaphragm is a dome of muscle under your ribs. It flattens to pull air in, and relaxes back up to push air out. A steady push is a steady note — which is why singers talk about breath before they talk about anything else.
Breathes in, holds, then sings “ah” at 220 Hz for 4.5 seconds.
2 · the source
Looking straight down the throat at the vocal folds. Air rushing past makes them slap open and shut — and the number of closures per second is the pitch.
220 Hz
= 220 closures every second
Far too fast to see, so this drawing is slowed 80× — about 2.8 openings a second on screen.
one flash = one closure
register
chest voice
short, thick folds vibrating through their whole depth — strong and speech-like
Watch the inset as you slide: low down the folds are short and thick; high up they are stretched long and thin, like tightening a guitar string. Typical adult folds are roughly 12–25 mm long — a child’s are shorter and thinner all round, which is why children’s voices sit higher.
3 · the filter
The tube above the folds doesn’t make the pitch — it shapes it, boosting two bands of frequency called formants. Move your tongue and lips and the vowel changes while the pitch stays put.
source pitch = 130 Hz — the same for all three
“ah”: F1 = 800 Hz, F2 = 1150 Hz
tongue low and flat, jaw dropped, lips relaxed
The other two you will meet: “oh” (500/900Hz) and “eh” (550/1800 Hz) — hear all five in the shape of a vowel →
the maths of your voice
Pitch is a count.
Hertz is not a mysterious unit. It means per second. So 220 Hz is simply 220 closures every second — your folds, banging shut, that many times, while you hold one note.
Hold it for four seconds and they will have opened and shut 880 times.
Double it = one octave.
An octave is not an addition, it is a doubling. Twice as many closures per second and you land on the same note name, one octave higher.
Two dials, not one.
The source sets the pitch. The filter sets the vowel. They are independent, which is the reason you can sing words and a melody at the same time — one instrument, two controls.
For the classroom
listen to your voice
Tap start, then hum or sing a steady note. The panel shows your wave, your pitch in hertz, and the nearest note.
Your voice never leaves this device.
Hum or sing a steady note. Your voice draws itself — and never leaves this device.
the math & physics of this instrument
Each is a short lab you can run in front of a class — with a live microphone or a sound to poke and a “for the classroom” card at the end.
Sing into the mic and watch your own voice wiggle — steady notes draw tidy waves, higher notes wiggle faster.
Sing your lowest note, then your highest — and measure how many times your voice can double. That is your range in octaves.
Same pitch, different mouth shape — that is how “ah” becomes “ee”. Press a button and hear your throat’s secret filter.
Want the note names to make sense first? See any sound as a wave → or bring the voice to a class with the school workshops →
the maths & physics of this instrument
Everything else here makes its sound in one place. The voice makes it in two, and the split is the whole lesson: the cords make a buzz whose pitch you control, and the tube above them — throat, mouth, tongue, lips — decides which parts of that buzz survive. Change the filter without changing the buzzer and you have said a different vowel on exactly the same note.
Systems with independent inputs
The cords set the pitch. The shape of the mouth sets which frequency bands are amplified. Neither controls the other.
You can hold one steady and move the other, out loud, without any equipment.
open it →
The coordinate plane · reading a point
Two resonance peaks name the vowel: 'ah' at (800, 1150) Hz, 'ee' at (300, 2300), 'oo' at (300, 870). Plot them and each vowel is a point.
Every vowel you have ever said has an address on a graph, and your jaw and tongue are the two axes.
open it →
Logarithms · ratio not difference
Octaves = log₂(highest ÷ lowest). From 82 Hz to 330 Hz is log₂(4) = 2 octaves exactly.
Range is a ratio, not a subtraction — and the log turns it back into a number you can count.
open it →
Periodic functions · frequency
Sing into the microphone and the trace repeats. Count the repeats in a second and that is the pitch in hertz.
Your own voice, drawn as the wave, in real time.
open it →