Instrument-Aware (default)
Analyzes your stereo mix (mid/side + bands) and places elements with HRIRs for a natural, “mix-aware” stage. Best for music and dialogue clarity.
Virtual Surround (5.1/7.1)
Up-mixes stereo into a virtual 5.1/7.1 bed and renders to binaural. Great for films/games; tweak intensity, crossfeed, ITD and LFE.
Binauro is 100% community-funded — your support keeps it free
If Binauro helps you focus, relax, or create, consider a small donation. It covers servers and motivates me to keep going.
How the Binaural Renderer Works
We split the track into lows / mids / highs, place each band at realistic angles and distances, then convolve with measured HRIRs (ITD/ILD/head shadow). A light instrument detector routes bass, vocal, guitars, and hatsto their own emitters. Short early reflections and a tiny dark tail push the image out of your head, while adaptive width keeps the stage stable.
Input & Pre-Tilt
Loudness guard and a small diffuse-field high-shelf to keep HRIRs smooth.
3-Band Split
4th-order Linkwitz-Riley crossovers for lows/mids/highs.
HRIR Placement
Interpolated azimuth/elevation HRIRs for each emitter; true ITD/ILD and head shadow.
Instrument Scene
Bass center-low, vocal center-front, guitars L/R, hats high/wide. Instrument Focus blends scene vs neutral.
Room Cues
Multi-tap early reflections + very short dark tail for externalization without smear.
Adaptive Width
Mid/side and high-band energy gently nudge width and high-azimuth spread.
Polish
Tiny post high-shelf and soft saturation, then true stereo out.
Frequently Asked Questions
You can upload MP3, WAV, OGG, and most common browser-decodable formats. Decoding and processing happen locally in your browser.
Think of two virtual speakers around your head. We split the music into lows/mids/highs, place each range at sensible angles and distances, then filter each path with measured HRIRs (head-related impulse responses). Short early reflections and a tiny dark tail push the image out of your head. Result: an honest 3-D stage over headphones.
1) Loudness guard + tilt: gentle pre-trim and a small high-shelf to keep HRIRs smooth.
2) Band split: 3-way Linkwitz-Riley crossovers for lows/mids/highs.
3) HRIR placement: each band hits left/right/elevated emitters via interpolated HRIRs (ITD, ILD, head shadow).
4) Instrument scene: a light analyser estimates bass, vocal, guitars, hats and routes them to dedicated stage spots.
5) Room cues: early reflections from multiple sides + very short dark late tail.
6) Adaptive width: mid/side and high-band energy subtly widen or relax the stage on the fly.
7) Polish: tiny post high-shelf and soft saturation; then true stereo out.
Stage geometry. Higher values widen azimuths and increase band depth (lows a bit farther, highs slightly elevated). It is not a wet/dry knob.
It blends between a neutral stereo stage and an instrument-aware scene. As you raise it, bass anchors the center-low, vocals sit center-front, guitars spread left/right, and hats live higher/wider. A small vocal lock option keeps lead vocal centered when present.
Binaural cues rely on each ear receiving a different signal. Headphones preserve interaural time and level differences (ITD/ILD) that HRIRs create.
Use the Compare switch. It bypasses spatial processing in realtime so you can A/B against the untouched stereo file without stopping playback.
No. Reverb alone blurs depth; crossfeed alone narrows width. This engine uses true HRIR convolution per band and per emitter, plus controlled early reflections and gentle adaptive width for a convincing externalized image.
Only slightly, by design. A small pre-tilt protects against bright HRIR buildup, and a post high-shelf (Presence) lets you fine-tune air without harshness. The goal is spatial realism with minimal color.
It scales early reflections and the short late tail. More room increases externalization and envelopment; less room keeps it drier and closer.
No. Decoding, analysis, HRIR convolution, and rendering run fully in your browser. Nothing is sent to a server.
Export time scales with track length and your device’s CPU. Realtime preview starts immediately; offline rendering runs locally and completes when the browser finishes processing the full track.
Yes. Mono is treated as a centered source and spatialized through the same HRIR stage, so you still get a 3-D image.
More tools to help you
Binauro — The Free Binaural Audio Renderer & 3-D Sound Generator
Binauro is a free, browser-based tool that brings binaural beats, 3-D spatial audio rendering, and immersive sound design directly to your computer without downloads or subscriptions. Built entirely on the modern Web Audio API, it runs locally in your browser—meaning your audio stays private and no processing happens on remote servers. Whether you are a musician exploring psychoacoustics, a researcher testing head-related transfer functions (HRTFs), or a casual listener curious about binaural beats, Binauro gives you a full toolkit for experimenting with sound in virtual space.
The Science of Spatial Audio & HRTFs
Beyond beats, Binauro is also a 3-D audio renderer. This is achieved using head-related transfer functions (HRTFs). An HRTF describes how sound waves interact with the unique shape of your ears, head, and shoulders. By applying HRTF data to a stereo signal, we can simulate the exact timing and filtering cues that make sounds seem to come from specific directions in 3-D space.
Binauro uses the open KEMAR dataset—a standardized HRTF measurement widely used in psychoacoustic research. Our system is designed to expand toward personalized HRTFs in SOFA format, which can improve localization accuracy even further.
Features of the Binauro Renderer
With Binauro you can:
- Upload your own audio files (WAV/MP3) and place them in 3-D space.
- Apply occlusion filters, equalizers, and early reflections for realism.
- Use real-time processing directly in your browser with no latency.
How Can Binaural Audio Be Used?
Binaural audio is not limited to wellness apps. It is actively used in:
- Virtual Reality (VR) and Augmented Reality (AR) for immersive soundscapes.
- Game audio design to position effects and voices around the player.
- Film and music production to create spatial depth without expensive hardware.
- Meditation and therapy apps to guide focus and relaxation.
- Academic research in neuroscience, psychoacoustics, and auditory perception.
Get Started with Binauro
Curious to try it? Visit the Binaural Beats Generator for quick presets like focus 10 Hz or deep relaxation 4 Hz. Then dive deeper with our 3-D Audio Renderer, where you can position multiple sounds around your head and experience true spatial immersion.
For deeper learning, check out our blog articles on spatial audio covering topics such as Dolby Atmos, DTS:X, Ambisonics, and psychoacoustic research. These resources help bridge the gap between practical use and theoretical understanding.
Tags: binaural beats, 3-D audio, spatial audio, HRTF, psychoacoustics, ambisonics, virtual reality sound, Web Audio API, sound localization.