Sine, Square, Sawtooth and Triangle Waves — hear them

Listen to the waves

Tap a wave to play it, and again to pause. All play at 220 Hz, so only the shape changes. The picture shows the wave itself; the Harmonics tab shows what it is made of.

Why the shape changes the sound

Any repeating wave can be built from sine waves at whole multiples of its frequency: its harmonics. A sine wave is the pure case, one frequency and nothing else. A square wave has only the odd harmonics, falling as 1/n, which makes it hollow. A sawtooth has all of them, which makes it bright and buzzy. A triangle has the odd ones, falling much faster, so it sounds soft, close to a sine.

That is why synthesizers start from these shapes: a filter can then remove harmonics to shape the sound, which is called subtractive synthesis. A pulse wave thinner than a square sounds nasal, and noise has no pitch at all: every frequency at once.

Good to know

Joseph Fourier showed in the early 1800s that any repeating wave is a sum of sine waves: the idea behind every spectrum on this site.
Built from sines, a square wave always overshoots at its edges by about 9%, however many harmonics you add: the Gibbs phenomenon.
The Nintendo Entertainment System had five sound channels: two pulse waves, a triangle, a noise channel and short samples. Its music is made of exactly these shapes.
Classic Moog synthesizers start from a sawtooth or square and carve it with a low-pass filter.

Wave	Its harmonics	How it sounds
Sine	Only the fundamental	Pure, flute-like
Square	Odd ones (1, 3, 5…), each 1/n	Hollow, clarinet-like
Sawtooth	All of them, each 1/n	Bright, brassy, buzzy
Triangle	Odd ones, each 1/n²	Soft, rounded
Pulse (25%)	All but every 4th	Nasal, like old game consoles
White noise	Every frequency, no pitch	A hiss

What does a sine wave sound like?

Pure and plain, like a tuning fork or a soft whistle: it has a single frequency and no harmonics.

What is the difference between a square and a sawtooth wave?

A square wave has only the odd harmonics, so it sounds hollow; a sawtooth has all of them, so it sounds brighter and buzzier.

Why does a triangle wave sound like a sine?

Its harmonics fade very quickly (as 1/n²), so little but the fundamental is left: it is a sine with a little edge.

Mixes

Pick what you need. One tap to start, change anything and save it as your own.

Focus timer

Work in waves.

The Pomodoro rhythm: focus with calm sound in your ears, then take a real break. A soft bell marks every change, so you never watch the clock. Every fourth break is a long one.

25:00Focus · 1 of 4

Silence during breaks

Sound while you work

Breathe

Slow your breathing down.

Follow the circle and the sound: it rises as you breathe in and falls as you breathe out. Choose a rhythm, or set your own, and pick what plays underneath.

Ready

Sound while you breathe

Noise generator

Any color of noise, from deep brown to bright violet — and everything in between.

Brown noise

Noise volume

Spectrum · 20 Hz – 20 kHz

Sound science

The colors of noise

Same randomness, different tilt. Each color shifts energy between low and high pitches — here is what that sounds like.

White

0 dB / octave

Equal energy at every frequency. Because we hear in octaves, it sounds bright and hissy — the classic "TV static".

Pink

−3 dB / octave

Equal energy in every octave, so it sounds even to the ear. Steady rain, rustling leaves. A favorite for focus.

Brown

−6 dB / octave

Deep and warm, like a distant waterfall or a plane cabin. Masks voices and traffic without any hiss.

Grey

Equal-loudness curve

Shaped around how our hearing works, so every pitch seems equally loud. Balanced and soft.

Blue

+3 dB / octave

The mirror of pink: more treble than bass. Airy, crisp, like a light spray.

Violet

+6 dB / octave

Mostly treble, like hissing water. Sometimes used to mask high-pitched ringing.

Calm

Gentle tones to settle into: singing bowls, a slow warm drone, wind chimes tuned so every note fits.

Frequencies

Famous tones on pages of their own: hear them side by side, with honest facts.

Sound phenomena

How sound bends, shifts, rings and fools the ear, and why space is silent: hear it for yourself.

Nature

Rooms & travel

Animals & countryside

A purring cat, whales and dolphins, a nightingale in the dark, cowbells on a summer pasture. Wonderful in stereo.

For babies

Womb sounds are what a baby heard for nine months: a deep rush of blood flow, and the heartbeat.

Hearing and speaker tests

Check your ears, headphones and speakers, each test on a page of its own with a live picture.

Ear Age · 60 seconds

Test your ears.

Our ears lose the highest pitches first, and it starts early. Find the highest tone you can still hear and see the typical age for it.

Headphones on, quiet room
Set a comfortable volume on the 1 kHz tone
Don't turn it up when a tone disappears — that's the point

20,000Hz

Can you still hear it?

Hearing age test →

More ear tests

Check your headphones, find the deepest bass your setup can play, or play any pitch you like.

Headphones check

Left & right

Each ear should get its own side. It matters for 8D, binaural beats and every stereo sound here.

Headphones on, then tap a side.

Bass test

How low can you go?

Deep tones from 200 Hz down to 20 Hz, the bottom of human hearing. Mostly it tests your speakers or headphones.

Tone generator

Any pitch, 20 Hz – 20 kHz

Hz

Tone volume

Start quiet: high tones and square waves get tiring fast.

Take it to bed

An app without the app store.

Add Ears & Waves to your home screen and it opens like any app — full screen, with its own icon. Everything it needs is saved on your device, so it keeps playing on a plane, in a tent or with Wi-Fi off.

Preparing offline mode…

Works offlineNo streaming. Sound is computed on your device, forever.
Screen offKeeps playing with the phone locked. The timer fades it out gently.
PrivateNo account, no ads, no cookies. Your mixes stay on your device.

Sine, square, sawtooth.