White
0 dB / octave
Equal energy at every frequency. Because we hear in octaves, it sounds bright and hissy — the classic "TV static".
Beat frequency.
Two tones a few hertz apart swell and fade in a steady pulse. Hear one beat a second, four, ten and thirty, and a string being tuned until the beats stop.
Now playing
Deep sleep
Listen to the beats
Tap an example to play it, and again to pause. Count the swells: their rate is the difference between the two tones, and the live picture draws them. Any speakers work, except for the binaural beat, which needs headphones.
How beats work
Two tones of slightly different pitch drift in and out of step. When their peaks line up they add up and the sound is loud; half a cycle of drift later one pushes as the other pulls, and they cancel. The sound swells and fades as many times a second as the two frequencies differ: 440 and 444 Hz beat four times a second.
Musicians tune with it. Play two strings that should match: a slow wobble means they are slightly apart, and as you bring them together the beats slow down and stop. Past about 15 to 20 beats a second the ear hears no more pulses but a rough, buzzing tone; further apart still, two separate notes.
Good to know
- The beat rate is simply the difference of the two frequencies; the tone you hear sits halfway between them, 442 Hz for 440 and 444.
- Piano tuners count beats on purpose: in equal temperament each fifth is tuned to beat slowly at a set rate.
- A binaural beat is different: each ear gets one tone, so nothing cancels in the air. The beat is put together in the brainstem.
- Pilots of twin-propeller planes match the engines by ear: until they do, the cabin fills with a slow “wah-wah” of beats.
| Tones | Difference | What you hear |
|---|---|---|
| 440 + 441 Hz | 1 Hz | One slow swell a second |
| 440 + 444 Hz | 4 Hz | A clear, countable pulse |
| 440 + 450 Hz | 10 Hz | A fast flutter |
| 440 + 470 Hz | 30 Hz | Roughness, too fast to count |
| 440 left, 444 right | 4 Hz | A binaural beat, only in headphones |
What is the beat frequency?
The rate of the swells you hear when two close tones sound together. It equals the difference between them: 440 Hz and 443 Hz beat three times a second.
How do musicians use beats to tune?
They play the note against a reference and adjust until the beats slow down and disappear: no beats means the two pitches match.
What is the difference between beats and binaural beats?
Ordinary beats happen in the air, so any speaker plays them. Binaural beats need headphones: each ear hears one tone, and the pulse is created inside your head.
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.
Every fourth break is twice as long.
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.
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
Step 1 · Volume
Play the reference tone and set your volume so it's clear but comfortable. Leave it there.
Step 2 · Listen
8,000Hz
Your result
8k12k16k20k
A rough guide, not a diagnosis. Your phone, headphones and even this browser can cut the highest tones. Worried about your hearing? See an audiologist.
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.
200Hz
Your setup plays down to
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.
