Summary: macOS normally restricts system-level Spatial Audio (HRTF processing of 5.1/7.1 content) to AirPods and built-in speakers. By creating a specific Aggregate Device configuration, you can trick the OS into performing the binaural rendering and routing the processed audio to any USB DAC or wired headphone output. Result Surround sound content played through standard stereo headphones sounds directional/atmospheric rather than just left/right.
| Term | Definition |
|---|---|
| HRTF | Head-Related Transfer Function. Mathematics that simulate how ears perceive directional sound. |
| Binaural | Audio mixed for two ears to create a 3D effect via headphones. |
| Spatial Audio | Apple's implementation of converting surround sound (5.1/7.1) to binaural stereo using HRTF. |
| Item | Requirement |
|---|---|
| OS | macOS Monterey (12.0) or newer. |
| Hardware | USB DAC, USB-C dongle, or wired headphones visible in Audio MIDI Setup. |
| Player | IINA (free, open source) |
| Media | Video files containing 5.1 or 7.1 audio tracks (AC3, AAC, TrueHD, etc.). |
Press Cmd+Space, type Audio MIDI Setup, and press Enter.
Click the + symbol (bottom-left) → Create Aggregate Device.
- Select Built-in Output (or "MacBook Pro Speakers").
- Select your USB DAC (e.g., "FiiO BTR17" or "USB Audio Device").
- Critical: Ensure "Built-in Output" is the top item in the sub-device list.
Check Drift Correction for your USB DAC only. Do not check it for the built-in speakers.
Set the Clock Source dropdown (top of window) to Built-in Output.
- Click Configure Speakers… on the Aggregate Device tab.
- Set Configuration to Stereo.
- Map Left to your DAC's left channel (typically Channel 3).
- Map Right to your DAC's right channel (typically Channel 4).
- Click Apply.
Go to System Settings → Sound and set Output to your new Aggregate Device.
- Open IINA → Settings → Audio.
- Set Audio driver to AVFoundation (Required).
- Set Audio Device to your Aggregate Device.
macOS restricts the Spatial Audio rendering engine to "approved" hardware IDs. By creating an Aggregate Device where the Built-in Speakers are the master clock/device, macOS validates the chain as supported.
The channel mapping then routes the processed audio stream to channels 3/4 (your external DAC) instead of channels 1/2 (the internal speakers).
Why IINA? You must use a player that utilizes the AVFoundation driver. This accesses the high-level macOS media engine where the Spatial rendering occurs. Players like VLC use CoreAudio to talk directly to hardware, bypassing the rendering layer entirely.
| Device | Chipset | Status |
|---|---|---|
| Generic 3.5mm Output | Native Mac DAC | Working |
| FiiO BTR17 | ES9069Q (UAC 2.0) | Working |
| Firestone Audio Bravo | Tenor TE7022 | Working |
| Generic USB Bridge | XMOS U208 | Working |
| Application | Driver | Status |
|---|---|---|
| IINA (1.4.0+) | AVFoundation | Working |
| mpv | AVFoundation (--ao=avfoundation) |
Working |
| VLC | CoreAudio | Not Working (Might be config error) |
| QuickTime Player | N/A | Not Working |
| Apple TV App | N/A | Not Working |
Last updated: January 2026 macOS version: Sequoia (15.x)