No card required · 5-day full-access trial

Binaural audio,at its most honest.

Focus, shift gears, or settle down before sleep. Choose a sound for the moment and BIFROST generates separate left and right audio on your device in real time. See the live frequencies and their difference on screen as you listen.

✓ Free to use with no time limit.✓ No installation required✓ No card for the 5-day trial

The BIFROST home screen, showing ten purposes to choose from

Ten goal-based sessions

Layer 19 background sounds while monitoring carrier margin

125

A 125-column CSV after each session

Choose a sound for the moment

See live frequencies and their difference

Save a signal log for each session

Start here

What are binaural beats and amplitude modulation?

Both deliver rhythm through sound, but they work—and feel—differently. A binaural beat is perceived from the frequency difference between the ears; AM creates rhythm by changing the loudness of the sound itself. BIFROST uses each where it fits the listening device and your intent.

MECHANISM 01

Headphones or earphones required

Binaural beats

When each ear receives a slightly different frequency, you can perceive a third rhythmic pulse at the difference between them. With 263Hz on the left and 249Hz on the right, that pulse is 14Hz. BIFROST offers this gentle rhythmic cue for listening environments built around focus, unwinding, meditation, or sleep preparation. Headphones or earphones are required to keep the channels separate.

L 263Hz / R 249Hz

= a 14Hz pulse

Why people use it

Binaural beats are commonly explored as part of routines for focus, relaxation, meditation, or winding down before sleep.

When AM is enabled in headphone mode, it modulates the carriers only. The background remains unmodulated, preserving the shape of music and ambience.

MECHANISM 02

Designed for speaker playback

Amplitude modulation (AM)

AM makes the selected noise, ambience, or music rise and fall in loudness on a repeating cycle. It gives the sound a clear rhythmic contour that is easy to follow, helping you settle into a session and find the pulse again if your attention drifts. Because the pulse is carried by the sound itself, it remains audible through speakers.

The loudness itself rises and falls on a cycle

Why people use it

AM creates a clearly repeating rise and fall in loudness, adding a pulse you can hear and follow without having to understand the technology behind it.

In headphone mode, AM can be applied only to the carriers while music stays intact. In speaker mode, it shapes the selected source itself. This is a different experience from binaural playback.

Two rhythms. One listening environment shaped for your moment.

A binaural beat can create a gentle pulse perceived between the ears, while AM gives the sound an audible rise and fall. BIFROST layers both with relaxation music, then lets you choose a session for focus, unwinding, meditation, or sleep preparation. The experience is personal—listen and decide how it fits your routine.

BIFROST is developed as an acoustic tool, not a medical device. It is not intended to diagnose, treat, cure, or prevent any condition. Experiences vary.

Hear the difference

Preview BIFROST binaural audio.

This 18-second preview combines a higher-frequency binaural carrier pair, synchronized AM, DNEQ ULTRA, and BIFROST relaxation music.

BIFROST binaural signal chain

Still Water · 432 INTELLECTUAL CALM

Ready to play0:00 / 0:18

L 432 HzR 422 HzΔ 10 Hz10 Hz AMDNEQ ULTRA

Headphones or earphones are required for binaural separation. Through speakers you may still hear the carriers and AM pulse, but the left and right signals will not remain isolated. Start at a low volume.

For relaxation, choose binaural you can see and tune.

BIFROST brings a live binaural signal, synchronized AM, DNEQ ULTRA, and calm music into one adjustable listening space. If the preview feels right, shape the full experience for your own wind-down routine.

No card for the 5-day trial · No installation required

For moments like these

The right sound for this moment.

When getting started feels difficult, when you need to shift gears, or when you want a quieter end to the day. Choose what you need right now and begin.

Focus

Give one task your attention

For the moments when distractions keep you from beginning. Set aside time to turn your attention to the task in front of you.

FOCUS · STUDY / available on FREE

Reset

Make room between tasks

Between meetings or before moving to the next task. Pause for a moment and create some space to shift gears.

BREAK · BALANCE

Rest

Ease into a quieter evening

For nights when thoughts keep circling. Step back from the day's stimulation and make time to settle down quietly.

SLEEP · REST

How it works

From playback route to sound, without the detour.

Choose headphones or speakers first. BIFROST then shows only the settings that belong to that route, with a final review before playback.

Choose your playback route

For headphones, choose one of ten goals. For speakers, choose the source that will receive AM. Speaker playback is available on FULL ACCESS.

Choose the session or source

For headphones, set a goal and add background audio if you want it. For speakers, choose noise, nature audio, relaxation music, Player, or SAOR.

Review and play

Review the goal, background, output, and duration for headphones—or source, duration, volume, and AM for speakers—then start.

The BIFROST sound composition screen, layering a background sound

The BIFROST live monitor showing BINAURAL SYNC: SECURE, L-CH 262.72Hz / R-CH 248.72Hz, and a frequency matrix with SET, OUT and DRIFT

The current gap

A label describes the intent. It does not show the signal at playback.

A track name can describe how it was made, but it cannot show the live left–right difference, phase, or carrier-to-background level. BIFROST presents those as in-app measurements.

What you can verify

Prerecorded track

BIFROST

Audio source

Prerecorded trackA fixed audio file

BIFROSTThe production design and live playback state are different things

Live signal

Prerecorded trackStated in the title or description

BIFROSTA number on the label is a claim, not a measurement

Carrier/background overlap

Prerecorded trackNot visible

BIFROSTBackground audio can overlap the carrier band

Session data

Prerecorded trackNo session log

BIFROSTA 125-column CSV after each session

Ways to adjust

Prerecorded trackSwitch tracks

BIFROSTSimple at the surface. Deep when you need it.

During playback the DNEQ attenuation is shown as an operating mode; the figures themselves are written to the post-session log. Where that line falls is published too.

Features

Simple at the surface. Deep when you need it.

Start by choosing headphones or speakers. Headphone mode sets a goal and optional background; speaker mode selects a source and AM. Studio, Player, and SAOR add deeper control when you need it.

Ten goal-based sessions

FOCUS and STUDY are available on FREE. The remaining eight unlock with FULL ACCESS.

Layer 19 background sounds while monitoring carrier margin

Core set on FREE / all 19 on FULL ACCESS

Ten variable programs that change over time

Instead of a fixed frequency, the frequency and beat follow a designed curve as the session progresses. From the opening to the final stretch, it is never the same sound.

Use your own audio with Player and SAOR

Player loads files from your device; SAOR captures audio playing on your PC. Headphone mode combines that source with the carriers, while speaker mode applies AM to the selected source itself.

The BIFROST background library with noise, environment, and relaxation music categories

Proof

Go beyond guesswork.

BIFROST shows the signal being generated and processed inside the app, then saves a session log. Check your settings and playback conditions without relying on impressions alone.

SET → OUT

The preset target beside the current in-app generated value. DELTA reads 14.0 Hz on both rows.

DRIFT −0.27Hz

The carrier is wandering. That is the 1/f drift doing its job — exactly as specified.

Verification log

Carrier frequencies, beat difference, the state of each DSP process and how the measurements moved, recorded as a time series. Export it and check for yourself.

Generated at playback

The left and right carriers are generated live on your device rather than played from a distributed recording. The live monitor shows the signal inside BIFROST; processing added later by the OS, connection, or playback hardware is outside its measurement scope.

See the in-app signal state

The app analyzes its audio signal continuously and keeps phase, spectrum, and carrier-to-background levels on screen. It does not measure sound pressure at your ears or perception.

If it falls short, you can fix it

When conditions are not met, the reason is shown as well. The volume, the output route, or the layered sound. Once you know the cause, the next move is obvious.

Defined design range

A clear boundary for everyday listening.

BIFROST's phase-synchronized AM operates above 0 Hz and below 30 Hz. At 30 Hz and above, it bypasses automatically. This limit describes product behavior, not medical efficacy.

On the patent

The core signal control architecture is the subject of an application filed with the Japan Patent Office (application 2026-099039, June 2026, together with a priority-claiming follow-on). “Patent pending” indicates that an application has been filed. It does not guarantee that a patent will be granted, nor define any scope of rights.

Read the engineering note →

Pricing

Choose the level of control you need.

FREE keeps its current features. FULL ACCESS is the only paid plan and includes every BIFROST feature. Try everything free for five days before choosing.

FREE

A core set you can start with now

✓FOCUS and STUDY
✓White / pink / brown noise
✓Ocean and wind, two relaxation tracks
✓Headphone playback
✓Live monitor

Start on FREE

Recommended

FULL ACCESS

$9.99/ month

Every BIFROST feature, in one plan

✓Every current BIFROST feature
✓Studio: 10 programs whose sound shifts over time
✓Layer over your own music or work audio (Player / SAOR)
✓Spatial calibration and Octave Shift

Start 5-day free trial

The 5-day trial unlocks every FULL ACCESS feature with no card required. After the trial, you return to FREE automatically and are not charged.

Questions, answered plainly

Before you press play

Do I need a credit card for the free trial?+

No. You can start the 5-day FULL ACCESS trial without entering any card details, and nothing is charged automatically when it ends.

How is this different from white noise?+

White noise masks distracting sound, and BIFROST includes three types of noise too. On top of that, BIFROST generates separate carriers for your left and right ears on the device, with a designed frequency difference between them. Beyond simply masking, you can see what frequency is playing on screen and match it to what you're doing.

What exactly makes this different from tracks on YouTube?+

YouTube plays a finished audio file. BIFROST generates the left and right carriers on your device and displays their beat frequency, phase, spectrum, and carrier-to-background S/N inside the app. The monitor reflects BIFROST’s internal signal; later processing by the OS or playback hardware is outside its scope.

Are headphones required?+

Binaural playback requires headphones or earphones to deliver separate carriers to the left and right ears. Speaker mode on FULL ACCESS is a separate method that applies AM to the selected source; it does not play binaural carriers through speakers.

Is it safe to use? Is there anyone who shouldn't?+

BIFROST is an audio tool, not a medical device. Don't use it while driving, operating machinery, or in any situation that needs your attention. If you have a history of epilepsy or seizures, a heart condition, a pacemaker, a psychiatric or neurological condition, hyperacusis, or are pregnant or may be pregnant, please consult a physician before use. Start at a safe volume and stop immediately if you feel unwell.

Can I use it while under medical care or on medication?+

BIFROST is an audio tool, not a treatment. If you have a medical condition or are under care or on medication, please consult your doctor before use, just to be safe. BIFROST is not a substitute for medication or medical treatment.

What if I don't notice much of an effect?+

Responses vary from person to person. First, use headphones or earphones (binaural needs left/right separation), in a quiet environment, with a session that matches your goal. Start at a low volume and adjust; if you layer a background sound, DNEQ can protect the carrier's frequency band. BIFROST doesn't guarantee a specific effect — it's a tool that lets you adjust your own conditions and see for yourself.

Can I preview Studio on FREE?+

Studio and its ten variable programs are available only with FULL ACCESS. During the 5-day FULL ACCESS free trial, all current features, including Studio, are available without restriction.

Can I cancel at any time?+

Yes, from inside the app. Cancelling stops the next charge, and access continues until the end of the current billing period. Payments are processed by Stripe.

Contact / Technical Support

Have a technical question? Talk to the team building BIFROST.

Use this form for technical support, deployment questions, billing, or account issues. Requests are reviewed by Cloud Nine LLC, the team operating BIFROST, and routed by priority.

Legal Contact: info@cloud9llc.jp
Product Support Fallback: info@bifrostaudio.com
Operator: Cloud Nine LLC
6-665-1 Gakuen Yamato-cho, Nara, Nara 631-0041, Japan

Medical & Legal Disclaimer

BIFROST is a general-purpose audio tool, not medical care or a medical device. It does not diagnose, treat, cure, or prevent disease. Never use it during driving or hazardous work. For an implanted medical device, follow your doctor’s and manufacturer’s instructions and keep magnets and wireless equipment at least 15 cm (6 in) away unless stricter guidance applies. Stop immediately if you feel unwell.

NOT A MEDICAL DEVICE

BIFROST is offered as a general-purpose binaural audio tool, not as medical care or a medical device. It is not intended to diagnose, treat, cure, mitigate, or prevent any disease or condition. Any perceived effect is subjective and not clinically validated.

PROHIBITED USES

You must not use BIFROST while operating a motor vehicle, heavy machinery, industrial equipment, or in any situation where impaired environmental awareness poses a risk to yourself or others. Binaural audio alters perceptual state; such use could result in serious injury or death.

HEALTH CONDITIONS — CONSULT A PHYSICIAN

If you have or suspect you have epilepsy or a history of seizures; cardiac conditions or arrhythmias; a pacemaker or implanted cardiac device; a psychiatric or neurological disorder; sound sensitivity; or if you are pregnant or trying to become pregnant — consult a licensed physician before using BIFROST. If you use an implanted medical device such as a cardiac pacemaker, follow instructions from your doctor and the device manufacturer; as a general rule, keep magnets and wireless equipment, including your device and earphones or headphones, at least 15 cm (6 in) from the implant, unless a stricter individual instruction applies. Stop use immediately and seek medical attention if you experience seizure, chest pain, severe dizziness, disorientation, nausea, or any unusual symptom.

LIMITATION OF LIABILITY — USE AT YOUR OWN RISK

Use BIFROST responsibly and follow these safety instructions. Liability is governed by the Terms of Service; nothing here excludes liability or consumer, privacy, conformity, refund, withdrawal, or other rights that cannot be limited under applicable law.

USE BY MINORS

Children under 13 may not use BIFROST. A minor aged 13 or older may use it only with consent from a parent or legal guardian and an age-appropriate, supervised session length.