Why headphones required?

Binaural perceptual beat requires each ear to receive only one tone. Without headphones the tones mix in air and produce ordinary physical amplitude-modulation beating instead. Speakers work for the tool but the binaural effect is not present.

Research uses 100–500 Hz. Below ~50 Hz tones fuse into single pitch; above ~1000 Hz beat perception weakens. Default 200 Hz is the sweet spot. Lower base for delta/theta, higher for beta/gamma.

Generally yes at moderate volume. Avoid if you have epilepsy/seizure disorder (consult doctor first). Keep volume moderate. Don't use while driving (delta/theta can induce drowsiness). Not medical treatment — see clinician for sleep/anxiety/attention conditions.

Why only two spectrum peaks?

Each channel is a pure sine. L+R sum shows only two spectral lines. The 'beat' isn't a third line — it's an interference pattern in the auditory system. Waveform plot shows the interference envelope.

Can I sleep with this?

Delta preset (2 Hz) targets sleep induction. Use session timer (60 min common) for graceful fade-out. Headphone comfort during sleep is an issue — pillow speakers or sleep-mask headphones often work better than over-ear cans.

Binaural vs isochronic vs monaural?

Binaural: two tones, one per ear, brain constructs beat. Needs headphones. Monaural: two close tones mixed, physical AM beating, speakers OK. Isochronic: single tone pulsed on/off at beat frequency, strongest physical signal, no special playback needed.

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Binaural Beats Generator

A pure sine in your left ear at base frequency f, plus a pure sine in your right ear at f + beat — brain perceives a pulsing beat at |f_L − f_R|. Use the brainwave-band presets (delta, theta, alpha, beta, gamma) to target specific EEG ranges associated with sleep, meditation, focus, or peak cognition. Stereo headphones required — without separated L/R channels the binaural effect collapses into ordinary monaural beating.

⚠ Educational and exploratory tool. Binaural-beat research is mixed; effects vary by listener and are not clinically validated for treatment. Not a substitute for medical advice. If you have a seizure disorder, consult a doctor before using brainwave-entrainment audio.

Frequencies

Base (carrier) frequency 200.00 Hz

Log 50 Hz – 1 kHz. Typical binaural beats use 100–500 Hz carriers; the effect weakens outside that range.

Beat frequency 10.00 Hz

Linear 0.5 Hz – 40 Hz, 0.01 Hz resolution (Schumann 7.83 Hz preserved exactly). The brain perceives a pulse at this frequency.

Brainwave presets

Session timer

Time remaining

—:——

Audio fades over the last 8 seconds for a gentle session end.

Playback

Volume 30 %

Use headphones at comfortable, moderate volume. Loud isn't more effective.

Idle — press Play.

Live readouts

Left ear

200.00 Hz

Right ear

210.00 Hz

Brainwave band

alpha (α)

8–12 Hz · relaxed focus, calm awareness

Sample rate

—

AudioContext.sampleRate

L+R sum waveform (analyser live) — shows the visual "beat envelope"

Spectrum — log frequency · green = left ear · pink = right ear

Binaural Beats — What They Are and How They Work

A binaural beat is an auditory illusion: feed two slightly-different pure tones, one to each ear, and the brain perceives a third "beating" tone at the difference frequency — even though no physical signal at that frequency exists. The phenomenon was first described by Heinrich Wilhelm Dove in 1839 and has been studied periodically ever since, most actively in the context of brainwave entrainment beginning in the 1970s.

The math

f_{perceived beat} = | f_left − f_right |

Three parameters define everything: the base (carrier) frequency, the beat frequency you want to perceive, and the volume. This tool sends f_L = base to the left channel and f_R = base + beat to the right. Web Audio's ChannelMergerNode keeps the two signals in their own physical channels — without that separation (e.g. on mono speakers) you'd hear ordinary acoustic beating instead of the binaural perceptual beat.

EEG brainwave bands

Researchers typically target the beat frequency to match a standard EEG band:

Delta (δ): 0.5–4 Hz — deep dreamless sleep, healing, unconscious processing.
Theta (θ): 4–8 Hz — deep meditation, REM dreaming, creative flow, hypnagogic states.
Alpha (α): 8–12 Hz — relaxed alertness, calm awareness, light meditation, eyes-closed wakefulness.
Beta (β): 12–30 Hz — active thinking, focused attention, problem-solving, alertness.
Gamma (γ): 30–100 Hz — peak cognition, sensory integration, heightened perception. The 40 Hz frequency has the most research attention.

How to use this tool

Put on stereo headphones. The binaural effect requires physical channel separation.
Pick a brainwave-band preset (try alpha to start — it's the gentlest).
Set a session timer (15–30 minutes is typical for entrainment).
Find a quiet space, close your eyes, and let the tone play without trying to "force" any effect.
The audio will fade out gently at session end so you aren't startled.

About the visualization

The waveform plot shows the sum of L and R channels — what you'd hear if the two tones were mixed mono. That sum shows the classic "beat envelope" pattern at the difference frequency, which is the image most people associate with binaural beats. But the actual binaural perception works differently: each ear hears a clean steady tone, and the brain constructs the beat by comparing inputs from the two sides. The mono-sum view is educational but not what's happening in your head when wearing headphones.

Frequently Asked Questions

Do binaural beats actually work?

The science is mixed. Lab studies show that listening to binaural beats can produce small, statistically detectable EEG changes that follow the beat frequency. Whether those EEG changes translate to meaningful psychological effects (improved sleep, focus, anxiety reduction) is much less clear — some studies show modest effects, others show none. Individual variation is large. Treat this as an interesting auditory phenomenon worth trying, not a clinical intervention.

Why do I need headphones?

The binaural perceptual beat requires each ear to receive only one tone — that's the whole point. Without headphones (or with mono playback) the two tones mix in the air before reaching your ears, and you hear the ordinary physical "amplitude-modulation beating" between two close tones, which is a different phenomenon. The tool will play through speakers but the "binaural effect" you're trying to demonstrate won't be present.

Is there a "best" base frequency?

Research consistently uses base frequencies in the 100–500 Hz range. Below ~50 Hz the two tones approach the threshold where they'd fuse into a single pitch perception; above ~1000 Hz the beat perception weakens. The default 200 Hz is in the sweet spot. Lower base frequencies (100 Hz) work well for delta/theta; higher (300 Hz) for beta/gamma.

What's the Schumann resonance preset?

The Schumann resonance is the fundamental electromagnetic resonance of Earth's atmosphere at 7.83 Hz — a real geophysical phenomenon caused by global lightning activity exciting the Earth-ionosphere cavity. Some meditation traditions associate this frequency with "connecting" to the natural environment. The preset uses it as the beat frequency. Scientifically, it's just a beat-frequency target in the theta range; the geophysical connection is more metaphor than mechanism.

Is this safe?

Generally yes at moderate volume for short sessions. Cautions: (1) avoid binaural-beat audio if you have epilepsy or a seizure disorder — the brain-wave-entrainment principle could theoretically interact with seizure susceptibility (limited evidence, but consult your doctor); (2) keep volume moderate to avoid hearing damage; (3) don't listen while driving or operating machinery (the delta/theta states can induce drowsiness); (4) this isn't medical treatment — if you're managing a sleep, anxiety, or attention condition, see a clinician.

Why does the spectrum show only two thin peaks?

Because each channel contains a single pure sine tone (left at f_L, right at f_R). The L+R sum analysed by the spectrum view shows just those two frequencies as separate spectral lines — no harmonics, no broadband content. The "beat" you perceive isn't a third spectral line; it's an interference pattern in your auditory system. The waveform plot above shows the envelope of that interference.

Can I leave this running while sleeping?

The delta preset (2 Hz) is specifically designed for sleep induction. Use the session timer (60 min is a common duration) so the audio fades out gracefully rather than running all night. Sleeping with headphones can be uncomfortable; many users get better results from gentle pillow speakers or a soft sleep-mask with embedded headphones rather than over-ear cans.

How is this different from "isochronic tones" or "monaural beats"?

Binaural (this tool): two different tones, one per ear, brain constructs the beat perceptually. Requires headphones. Monaural beats: two close tones mixed into a single channel; the beat is a physical amplitude-modulation pattern in the audio. Works on speakers. Isochronic tones: a single tone pulsed on and off at the entrainment frequency. The strongest physical signal at the beat frequency; doesn't require special playback. All three are different routes to brainwave-frequency stimulation; isochronic is generally considered the most robust signal but binaural has the most research and the strongest tradition.

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