How Do I Set Up Multiple Audio Interfaces in Pro Tools?

Why Use Multiple Interfaces

Using multiple audio interfaces can help when you need:

• More microphone inputs for drums or orchestras
• Additional outputs for monitor mixes
• Combining specialized hardware interfaces
• Expanding I/O without upgrading a single device

Pro Tools can access all these devices as a single virtual interface.

Step 1: Aggregate I/O Setup (macOS)

1. Open Audio MIDI Setup → Window → Show Audio Devices.
2. Click the + button → Create Aggregate Device.
3. Select the interfaces you want to combine.
4. Set a clock source (choose the master interface to prevent clicks).
5. Label the aggregate device clearly.

Step 2: Multi-Interface Setup (Windows)

• Windows doesn’t support Aggregate I/O natively.
• Use a single ASIO-compatible driver for all interfaces if supported.
• Some manufacturers provide combined drivers for multiple devices (e.g., MOTU, RME).

Step 3: Configure in Pro Tools

• Go to Setup → Playback Engine.
• Select the Aggregate Device (macOS) or main driver (Windows) as the Playback Engine.
• Verify all inputs and outputs appear in I/O Setup.

Step 4: Verify Clocking

• Multiple interfaces can create drift if clocks are not synced.
• On macOS, the Aggregate I/O device handles internal clocking.
• On hardware with word clock, ensure all devices share the same clock source.

Step 5: Test and Assign I/O

• Create test tracks and assign inputs/outputs to verify routing.
• Check for latency and phase issues.
• Adjust buffer sizes if needed for stable performance.

Common Use Cases

• Recording full drum kits with multiple mics
• Expanding studio setups without new interfaces
• Large ensembles or orchestral sessions
• Multi-room monitoring and recording

Best Practices

• Always designate one interface as the master clock.
• Keep firmware and drivers updated.
• Avoid combining interfaces with very different latency or sample rates.
• Test the setup thoroughly before recording sessions.

Final Thoughts

Setting up multiple audio interfaces in Pro Tools allows for greater flexibility in professional recording environments. Proper clocking, driver configuration, and testing ensure a stable, high-quality multi-interface setup.