Spatial: Binaural HRTF
The Binaural HRTF mode of the SPATIAL tab places a sound anywhere around your head — left, right, above, behind, near or far — on ordinary headphones. It's how a game or movie can feel genuinely three-dimensional through two earcups.
The advanced spatial models on this page (Enhanced, Immersive, Custom HRIR, surround folding, 3D positioning) are a Premium feature. The Generic model and the stereo tools are free.
A head-related transfer function describes how your head, shoulders and the shape of your ears subtly filter a sound depending on which direction it comes from. Recreate those filters on headphones and your brain perceives the sound as coming from a real point in space, not "inside your head".
Choosing a model
The Model HRTF row of buttons picks how the 3D filtering is computed — four options, all visible at a glance along with their Premium lock state:
- Generic — synthetic ITD/ILD — synthetic timing/level cues (Woodworth ITD + raised-cosine ILD). Light, no ear-shape cues. (Free.)
- Enhanced — synthetic pinna cues — Aura Mixer's own model, adding synthetic pinna (outer-ear) colouration for stronger front/back and height. (Premium.)
- Immersive — measured 3D audio — real measured HRTFs from a research database (SADIE-II), the most lifelike option. Selecting it reveals a second Profile dropdown: pick Reference A/B (neutral heads) or one of 18 measured personal profiles — audition a few and keep whichever localises best for your ears. (Premium.)
- Custom HRIR — import .wav / .sofa — load your own HRIR profile. Click IMPORT and choose a
.wavor.sofa(the AES69 standard) file; once imported it appears in the HRIR File list. (Premium.)
A big .sofa file (tens of MB, thousands of measurement positions) parses in the background with a progress notice, and only pays that cost once — reopening the app or switching channels reuses the already-parsed result instead of reparsing from scratch.
Treble softening (Custom HRIR)
An imported HRIR can sound slightly bright or harsh in the highs. The Treble softening slider — shown only when the Custom HRIR model is selected — applies a gentle high-shelf cut to the binaural output to take that edge off.
| Control | Range | Default | What it does |
|---|---|---|---|
| Treble softening | −6…0 dB | −1.5 dB | High-shelf cut on the binaural output. 0 = off; more negative = softer highs. |
It updates in real time (no reload) and is saved with the channel. Applying the shelf to the final binaural output is mathematically identical to baking the cut into every HRIR — convolution is linear — so it costs nothing extra while letting you dial it by ear.
Positioning a stereo/mono source
When the channel is mono or stereo, the source becomes a single point you place in 3D:
| Control | Range | Default | What it does |
|---|---|---|---|
| Azimuth | −180…+180° | 0 | Direction around you (0° front, ±90° sides, ±180° behind). Linked to the diagram dot. |
| Elevation | −90…+90° | 0 | Height — below, level, or above. |
| Distance | 0.1…10 m | 1 | How far away the source sits. |
| Distance Attenuation | 0…100 % | 50 | How strongly distance reduces level (realism of "far away"). |
Folding a surround source to headphones
If the channel's source is 5.1 or 7.1 (set in Channel Setup), Binaural HRTF instead folds all those speakers down to a 3D headphone image, with each speaker fixed at its real-world angle. The panel then shows per-channel levels — a slider (0…100 %) for each speaker (front L/R, centre, surrounds, etc.) so you can balance the fold.
This is the headphone-surround use case: feed a 7.1 game or movie into a channel and hear it placed around you on stereo headphones.
The surround→binaural fold runs first on the channel — before Gain, Gate, EQ and Comp — because those processors are stereo-only. Your channel EQ and Comp therefore shape the already-folded binaural signal, not the raw surround feed. (See How Audio Flows.)
This is different from the 5.1 / 7.1 output modes in the mode strip (which send to multichannel hardware) — those are coming soon. Folding a surround source to headphones works today.