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Dual Tone Generator

Two independent sine oscillators at once. Set each frequency, hear beats when they are close, phantom difference tones when they are loud and far apart - and every interval in between. For more oscillators, the multi-tone generator scales up.

440 + 443 Hz

≈ 3 beats per second

Two tones, three phenomena

Beats: set the tones a few hertz apart (440 + 443) and hear the volume pulse at exactly the difference rate - the effect every by-ear tuner relies on, taught in the tuning guide. Difference tones: with two loud high tones (2000 + 2500 Hz) many ears perceive a phantom low tone at 500 Hz - your cochlea doing nonlinear math. DTMF: telephone dialing is precisely two simultaneous tones - hear the real pairs on the DTMF page, or go past two oscillators with the multi-tone generator.

Dual Tone FAQ

What is a dual tone generator for?

Demonstrating beat frequencies (two close tones pulsing at their difference), producing difference tones, testing intermodulation distortion in equipment (feed two tones, listen for products that should not exist), and DTMF-style two-tone signaling experiments.

Why do two close frequencies pulse?

Their waveforms drift in and out of phase: aligned they add (loud), opposed they cancel (quiet), repeating at exactly the difference frequency. 440 Hz plus 443 Hz beats three times per second. Tuners exploit this - beats slow as pitches converge and stop at unison.

What is a difference tone?

A third tone your ear invents at the mathematical difference of two real ones - play 2000 and 2500 Hz loudly and a phantom 500 Hz appears. It is generated by nonlinearity in the cochlea itself: a genuinely psychoacoustic sound that is not present in the air.

How is this different from binaural beats?

Here both tones play in both ears and the beating physically exists in the air - speakers work fine. Binaural beats send one tone to each ear and the brain constructs the beat internally, requiring headphones. Our binaural beats generator covers that case.

Try Our Other Audio Tools

Online Tone Generator

Generate single tones with precise frequency control. Perfect for quick audio testing and tuning.

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Multiple Tone Generator

Play multiple frequencies simultaneously with independent volume and panning controls.

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Frequency Sweep Generator

Create linear or exponential frequency sweeps for speaker testing and room acoustics analysis.

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Binaural Beats Generator

Generate binaural beats for meditation, focus, and relaxation. Requires headphones for proper effect.

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DTMF Tone Generator

Generate telephone dial pad tones (Dual Tone Multi Frequency). Interactive touch-tone dial pad.

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Online Metronome

Professional metronome with tap tempo, time signatures, subdivisions, and tempo trainer for musicians.

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BPM Counter

Tap along to any song to find its tempo in beats per minute. Includes tempo markings reference.

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Chord Player

Hear major, minor, diminished, and seventh chords in every key. Block chords or arpeggios.

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Chord Progression Player

Hear classic progressions like I-V-vi-IV and 12-bar blues in any key at any tempo.

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Online Piano

Free browser piano with 3 octaves, note names, and computer keyboard support.

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Noise Generator

Generate white, pink, and brown noise for sleep, focus, tinnitus relief, and speaker burn-in.

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Instrument Tuner

Reference tuning notes for guitar, bass, ukulele, violin, cello, and more at concert pitch (A440).

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Subwoofer Test

Test your subwoofer with a 60-second frequency sweep (150Hz-1Hz) and individual bass test tones.

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Hearing Test

Test your hearing range from 8kHz to 20kHz. Find your hearing age and compare with averages.

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Solfeggio Frequencies

Ancient healing tones including 528Hz (DNA repair). For meditation, chakra activation, and spiritual healing.

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Speaker Balance Test

Test stereo balance with panning control and left/right channel testing. Perfect for speaker setup.

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Speaker Phase Test

Check speaker wiring polarity by comparing in-phase and out-of-phase test signals.

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Audio Latency Test

Measure your Bluetooth or system audio delay in milliseconds with a click-and-flash sync test.

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Spectrum Analyzer

Real-time frequency analysis of your microphone input with a live log-frequency display.

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Decibel Meter

Measure approximate sound levels with your microphone - live dB with min/avg/max tracking.

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Mic Test

Check your microphone in seconds: live waveform, level meter, and record-and-playback check.

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Interval Ear Trainer

Learn to recognize musical intervals by ear with quiz mode, score tracking, and song mnemonics.

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Pitch Pipe

Chromatic pitch pipe with all 12 notes across 3 octaves. Perfect for singers, choirs, and a cappella groups.

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Shepard Tone

Experience the auditory illusion of an infinitely ascending or descending tone. Mind-bending psychoacoustic phenomenon.

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Mosquito Tone

Can you hear the mosquito tone? High-frequency test (15-20kHz) that only young people can hear. Find your hearing age!

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Soundscape Builder

Create relaxing ambient soundscapes with singing bowls, nature sounds, and binaural beats.

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Fix My Speaker

Three sound modes to clean a muffled speaker: 165 Hz water eject, dust-shaking sweeps, and vibration.

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Water Eject Sound

Push water out of a wet phone or watch speaker with a pulsed 165 Hz tone - the same method Apple Watch uses.

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Dog Whistle

Adjustable high-frequency whistle (8-22 kHz) for dog training - clearly audible to dogs, silent to most adults.

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Isochronic Tones

Rhythmic pulsed tones across delta to gamma ranges. Stronger than binaural beats and works without headphones.

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Perfect Pitch Test

Name 12 random notes with no reference tone and find out if you have absolute pitch or great pitch memory.

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Vocal Range Test

Sing your lowest and highest notes and get your range plus voice type - bass to soprano. Mic-based, nothing uploaded.

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Hearing Age Test

Find the highest frequency you can hear (8-20 kHz) and see how old your ears test. Takes one minute.

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Vocal Remover

Instant karaoke via center-channel cancellation - free, unlimited, and processed locally.

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Voice Recorder

Record from your microphone and download as WAV - no signup, nothing uploaded.

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Volume Normalizer

Normalize any file to a LUFS target with true-peak protection instead of silent clipping.

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Drum Machine

16-step beat maker with synthesized 808-style drums, swing, and shareable pattern links.

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Audio Analyzer / LUFS Meter

Drop a file and get integrated LUFS, true peak, RMS, and a waveform - measured locally, nothing uploaded.

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Chromatic Tuner

Microphone tuner with a cents needle - play any note on any instrument and tune to ±5 cents.

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Headphone Test

Five-minute headphone checkup: channels, wiring polarity, bass and treble reach, and driver distortion.

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Surround Sound Test

Send noise to each 5.1 channel - fronts, center, surrounds, and subwoofer - and catch swapped or dead speakers.

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