How to Get Multiple Displays from an Apple Silicon Mac with Sonnet and DeckLink

If you’ve recently bought one of Apple’s latest Silicon Macs- whether it’s a Mac Mini, MacBook Air, or MacBook Pro- you may have run into a frustrating limitation. These machines only support one external display on the MacBooks and just two on the Mac Mini. This proves to be a problem if you need to run multiple displays for ProPresenter, live streaming, or other AV applications.

So, how do we get multiple displays from an Apple Silicon Mac? Let’s dive in and answer that question.

The Challenge with Apple Silicon and External Displays

Apple Silicon Macs are powerful, but they have a built-in limitation when it comes to external displays. Unlike Intel-based Macs, which could handle multiple displays through a variety of outputs, Apple Silicon devices rely on their integrated GPU and Thunderbolt/USB-C ports, limiting how many screens they can drive natively.

For MacBook Air models with Apple Silicon, you’re stuck with one external display unless you use special adapters or workarounds. The Mac Mini allows for two displays, but that’s still limiting for many professional setups- mainly because one of those displays is for the operator.

If you need more than the default number of displays, you’ll need an external solution—and that’s where Sonnet and DeckLink come in.

The Sonnet Expansion Chassis and DeckLink Duo

A great way to add multiple displays to an Apple Silicon Mac is by using a Sonnet Echo Express SE I Thunderbolt Expansion Chassis (or one of larger models) paired with a Blackmagic DeckLink PCIe card (I use a DUO in this application most times). This setup allows you to output multiple video signals over SDI, HDMI, or Fiber, which is ideal for broadcast, ProPresenter setups, and live production environments.

What is the Sonnet Echo Express SE I?

The Sonnet Echo Express SE I is a Thunderbolt-to-PCIe expansion chassis. This allows you to use full-size PCIe cards with your Mac. Here’s why it’s a great solution:

- Thunderbolt 3/4 Connectivity – Works seamlessly with all Apple Silicon Macs.

- PCIe Expansion Slot – Lets you add **video capture, output, or processing cards to your Mac.

- Compact and Portable** – Ideal for both permanent installations and mobile setups.

Using the Sonnet Echo Express SE I, we can install the DeckLink Duo to add multiple SDI video outputs to our Mac.

What is the Blackmagic DeckLink Duo?

The Blackmagic DeckLink Duo is a PCIe card that provides multiple SDI video outputs. It’s designed for broadcast professionals but is incredibly useful in church AV setups as well. Here’s what it offers:

- Multiple SDI Outputs – Allows you to connect four independent displays from a single Mac.

- Broadcast-Quality Video – Supports resolutions up to 1080p at 60Hz.

- Configurable Output Mapping – Customize how each port is assigned.

- Reliable SDI Connection – More stable than HDMI and avoids common handshaking issues.

By installing the DeckLink Duo into the Sonnet Chassis, we effectively bypass Apple’s display limitations and gain four additional outputs.

How to Set Up the Sonnet and DeckLink for Multiple Displays

Step 1: Connect the Sonnet Chassis to Your Mac

- Plug the Sonnet Echo Express SE I into your Mac via Thunderbolt.

- Ensure the power supply is connected to the chassis.

Step 2: Install the Blackmagic Video Desktop Software

-To get the DeckLink Duo working, download the Blackmagic Video Desktop application from the Blackmagic Design website. This software enables MacOS to recognize and manage the outputs properly.

Step 3: Configure the DeckLink Duo Outputs

- Open Blackmagic Video Desktop Setup after installation.

- You should see four independent outputs appear.

- Rename them for easy identification (e.g., "Projector Output," "ATEM Feed," "Lower Thirds," etc.).

- Set the appropriate resolution and frame rate for each display.

Step 4: Assign the Outputs in ProPresenter

If you’re using ProPresenter to drive your displays:

- Open ProPresenter and navigate to Preferences > Screens.

- Click Configure Screens and assign each Blackmagic output to a specific function (e.g., Main Screen, Lower Thirds, ATEM Feed, Stage Display).

- Choose the appropriate resolution and refresh rate.

Once everything is mapped correctly, ProPresenter will recognize each output as an independent display—allowing you to drive multiple screens with a single Apple Silicon Mac.

Why This Setup is Better Than Using HDMI Adapters

Many users attempt to expand their display outputs by using USB-C to HDMI adapters. However, these solutions have major drawbacks:

- Limited Resolutions & Frame Rates – Many adapters won’t support broadcast-friendly frame rates like 23.98fps or 59.94fps.

- HDMI Handshake Issues – HDMI connections can sometimes fail, especially in long cable runs or live production environments.

- Software Limitations – Some USB-C adapters require DisplayLink drivers, which add latency and compatibility issues.

With the Sonnet and DeckLink solution, you bypass these problems entirely. SDI connections are far more reliable, and DeckLink supports professional broadcast resolutions and frame rates that HDMI adapters often can’t handle.

Final Thoughts: A Scalable Solution for Apple Silicon Macs

If you need multiple displays for ProPresenter, live production, or broadcast work, using a Sonnet Echo Express SE I with a Blackmagic DeckLink Duo is a powerful, scalable solution.

Why This Setup Works Best:

✅ Works with all Apple Silicon Macs

✅ Provides up to four SDI outputs

✅ More reliable than HDMI adapters

✅ Supports broadcast-friendly resolutions & frame rates

✅ Future-proof and upgradeable

For church AV teams, this setup is an excellent investment. Whether you're running lyrics, live video, stage displays, or switcher feeds, this method ensures stability and professional quality without breaking the bank.

Learn more about the Sonnet and Decklink pair

If you have questions, feel free to email Justin@EnhanceAVL.com

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