EARS & WAVES

← Sound phenomena

Combination tones.

Play two high tones together and, listening closely, you hear a third, much lower one that is not in the sound at all. Your own ear makes it: Tartini’s “third sound”.

Now playing Deep sleep

Listen for the phantom

Tap an example to play it, and again to pause. Listen below the two whistles for a faint, low tone; a moderate volume is enough, so keep it comfortable. The picture marks where it would be: it is not in the sound.

How combination tones work

Your inner ear is not a perfectly linear microphone. When two tones reach it together, the cochlea’s response bends a little and creates new frequencies that were not in the air: most clearly the difference f2 − f1, and 2f1 − f2. Play 2000 and 2400 Hz and a faint 400 Hz appears, made by your ear itself.

Because the tone is made inside you, it moves with the two real tones: slide one of them and the phantom slides too, often in the opposite direction. Violinists use these tones to check the tuning of double stops, and scientists record them from the ear itself as otoacoustic emissions.

Facts that often get mixed up

  • A combination tone is not the missing fundamental: that is the brain recognising a pattern of harmonics, while this is a real distortion product of the ear.
  • The violinist Giuseppe Tartini described the “third sound” in 1754 and said he had found it decades earlier; the German organist Georg Andreas Sorge wrote about it in 1744.
  • The spectrum of the sound here shows only the two tones: the third one exists only in your ear, which is why the picture draws it as a dashed line.
  • The louder the two tones, the stronger the combination tone, which is why it is easiest to hear at moderate volume rather than very quietly.
Two tonesDifference tone (f2 − f1)Cubic tone (2f1 − f2)
2000 + 2400 Hz400 Hz1600 Hz
2400 + 3000 Hz600 Hz1800 Hz
2000 + 2200 Hz200 Hz1800 Hz
2000 + 2800 Hz800 Hz1200 Hz
What is a Tartini tone?

A combination tone: a third, lower note heard when two tones sound together, most often at the difference of their frequencies. It is produced inside the ear.

Why can’t everyone hear it?

It is faint and depends on the volume, the ear and attention. Try the sliding example: a low tone moving against the high ones is easier to notice.

Is it the same as beats?

No. Beats are a slow swelling of two close tones; combination tones appear when the tones are far apart and are heard as a separate pitch.

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

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
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

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.
Deep sleep