SOS: Audio Interfaces - Why Does My Audio Software Only See 2 Outputs From My 8-Channel Interface?

November 5, 2025

It’s tech week. Your show is built. You’ve got cues for the main PA, for the on-stage monitors, for the subs, and for the lobby speakers. You plug in your trusty 8-output USB audio interface, open your cueing software—be it QLab, Show Cue Systems (SCS), Canvas, Multitracks Playback, or even OBS for video—and... it only sees two outputs. "Speakers (L/R)".


You're losing time, the director is asking to hear the cue again, and you just need it to work.


Don't panic. This is one of the most common and frustrating problems in pro audio, and the fix is almost always the same. Your hardware is not broken. The problem is your drivers and configuration.



This guide will walk you through the fix for both Windows and MacOS.

For MacOS Users (QLab): The Answer is Audio MIDI Setup


On a Mac, the problem is different. MacOS uses "Core Audio," which is inherently multi-channel, so you don't need ASIO. If QLab only sees 2 outputs, it's almost always a configuration issue, not a driver issue.


Your 2-Step Action Plan (MacOS)


Step 1: Configure the Device in "Audio MIDI Setup"

This is the most critical step. You need to tell MacOS that your device is a multi-channel surround sound unit, not just a simple stereo headphone jack.

  1. Plug in your audio interface.
  2. Open "Audio MIDI Setup" (find it in Applications > Utilities).
  3. In the "Audio Devices" window, select your USB audio interface from the list on the left.
  4. Click the "Output" tab.
  5. Find and click the "Configure Speakers..." button at the bottom right.
  6. A new window will pop up. In the "Configuration" dropdown, change it from "Stereo" to "7.1 Surround" (or "Octaphonic," or whatever the highest channel count is).
  7. Click "Apply." You can leave the speaker assignments as they are.


Step 2: Map Your Outputs in QLab

Now that MacOS is exposing all 8 channels, QLab will see them.

  1. Open QLab and go to Settings > Audio.
  2. Select your interface as the device.
  3. Go to the "Device Routing" tab.
  4. You will now see a beautiful grid with all 8 (or more) outputs available. Map QLab's patch outputs (1, 2, 3, 4...) to the corresponding device outputs.

For Windows Users (SCS, Canvas, OBS): The Answer is ASIO


On Windows, this problem is almost always a driver issue.


The Problem: WDM vs. ASIO

When you plug in your interface, Windows tries to be helpful by using its built-in drivers (WDM, DirectSound, WASAPI). These are consumer-grade drivers designed to do one thing: let all your apps (Spotify, YouTube, system alerts) play sound out of one "Default Playback Device," which is almost always a 2-channel stereo pair.


Your professional cueing software (SCS, Canvas, etc.) looks at what Windows is offering, and Windows is only offering "Speakers (L/R)."


The Solution: ASIO

To get all 8, 16, or 32 outputs, you must bypass the Windows system mixer entirely. You need a dedicated "highway" that lets your cueing software talk directly to your audio interface. That highway is called ASIO (Audio Stream Input/Output).


When you use an ASIO driver, your software will no longer see "Speakers (L/R)". It will see the real hardware: "Interface Out 1," "Interface Out 2," "Interface Out 3"... all the way to your final output.

Your 3-Step Action Plan (Windows)


Step 1: Get the Manufacturer's ASIO Driver

This is the most important step. Do not rely on Windows "Plug and Play."

  1. Unplug your USB audio interface.
  2. Go to the manufacturer's website (Focusrite, PreSonus, Roland, Behringer, etc.).
  3. Navigate to the "Support" or "Downloads" section and find your exact interface model.
  4. Download the latest "Driver" or "Software" package for your version of Windows.
  5. Run the installer. This package is what installs the all-important ASIO driver.
  6. Restart your computer, then plug your interface back in.


Step 2: Tell Your Cueing Software to Use ASIO

This is the most common place to get stuck, as every program hides this in a different menu.

  • For Show Cue Systems (SCS): Go to Options in the main toolbar and select Audio Driver - ASIO (using BASS). This is the correct setting for multi-channel playback.
  • For Multitracks Playback / Canvas: Look in Settings > Audio. Ensure the "Audio Device" is set to your interface's ASIO driver, not WDM or DirectSound.
  • For OBS Studio: OBS's native ASIO support is tricky. You will often need a third-party plugin (like "ASIO for OBS") to add "ASIO Input/Output Capture" sources. In the plugin's properties, you can then select your ASIO driver and see all 8+ channels.


Step 3: Map Your Outputs in the Software

Just selecting the driver gives you access; it doesn't route the sound. Your final step is to tell the software where to send each cue.

  • In SCS: Go to the Editor > (Click the top "Production" icon) > Production Properties. Under the Devices > Audio Output tab, you will build your logical devices ("Mains," "Monitors," "Lobby") and map them to the "Physical Device" (e.g., "ASIO: Out 1-2," "ASIO: Out 3," "ASIO: Out 4").
  • In Canvas: Go to Settings > Audio. You'll find an output mapping grid to assign your buses (like "Tracks," "Click," "Guide," "Pad") to your hardware outputs (1, 2, 3, 4...).


Still Stuck? Check the Hardware Itself (All Platforms)


If your software still won't see all the channels, the problem is on the hardware.

  • Check Your Sample Rate: Some interfaces (like the Roland Octa-Capture) have a "high-quality" mode that reduces the channel count. If your interface is set to 192 kHz, it may be physically limiting itself to 4 outputs [cite: 8908, 8910-8912]. Check the hardware's settings or its software control panel and set the sample rate to 48 kHz or 96 kHz [cite: 8899-8907].
  • Check Your Interface's Control Panel: Open the interface's own control panel (the software you downloaded in Step 1). It may have an internal "Patch Bay" or "Mixer." Ensure that the audio from your computer (often labeled "WAVE OUT" or "DAW") is routed to your physical outputs [cite: 7999-8001, 8007, 8227-8228].
  • Check for "Streaming Mode": Many modern interfaces have a switch (physical or in software) that mixes everything down to 2 channels for streaming to Zoom or OBS. Make sure this mode is turned OFF.


That's it. 99% of the time, the path from 2-channel frustration to multi-channel glory is: Install/Check Driver -> Configure Software -> Map Outputs.

Now go run your cues.

Frequently Asked Questions (FAQ)

  • In Show Cue Systems (SCS), I selected ASIO, but I still only see 2 outputs.

    This almost always means your hardware is limiting the driver. For example, if you're using a Roland Octa-Capture, it is 100% in 192 kHz mode. Set it to 48 kHz on the device's SYSTEM menu to unlock all outputs [cite: 8901, 8905-8906, 8908, 8910-8912].

  • I see all 8 outputs in SCS, but no sound comes out of 3-8.

    This is the Octa-Capture's internal Patch Bay. Open the Octa-Capture Control Panel, go to the Device menu, and open Patch Bay. The "Source" for your outputs (e.g., OUTPUT 3-4) is probably set to DIRECT MIX A [cite: 8870-8872]. Change this! The "Source" for all outputs you want SCS to use must be set to the corresponding WAVE OUT (e.g., WAVE OUT 3-4) [cite: 8864, 8893-8894].

  • I'm using QLab on my Mac, but it's not seeing all 8 outputs of my interface. How do I fix this?

    1. Check your interface's sample rate. If it's 192kHz, set it to 48kHz or 96kHz.
    2. Open "Audio MIDI Setup" on your Mac (in Applications > Utilities).
    3. Select your interface, click the "Output" tab, and click "Configure Speakers..."
    4. Set the speaker configuration to "7.1 Surround" or the highest channel count and click "Apply".
    5. In QLab, go to Settings > Audio > Device Routing and verify all outputs now appear in the grid.

  • How do I get my 8-channel interface into OBS?

    OBS's native Windows support for multi-channel ASIO is very limited. The best way is to use a dedicated plugin like "ASIO for OBS" (or "NDI Tools" as a workaround). This adds new "ASIO Input/Output Capture" and "ASIO Output Capture" sources in OBS, allowing you to select your ASIO driver and map all 8+ channels as separate sources.

  • In Multitracks Playback or Canvas, how do I get the Click Track to a different output?

    This is exactly what ASIO is for. In Settings > Audio, make sure your ASIO driver is selected. Then, go to the output mapping or "Buses" section. By default, all buses (Tracks, Click, Guide, Pad) are sent to Out 1-2. Change the "Click" bus to output to a different channel, like "ASIO: Out 3," and the "Guide" to "ASIO: Out 4."

  • I installed the ASIO driver, but my software still doesn't show it.

    Try restarting your audio software. If it's still not there, restart your computer. This forces Windows and your software to re-scan for all available audio drivers.

  • Can a Windows Update break my ASIO drivers?

    Yes. A major Windows update can sometimes reset audio driver priorities or permissions. This is why "Get the latest driver from the manufacturer" is the first step. Re-installing the manufacturer's driver after a Windows update often fixes the problem.

  • What is ASIO4ALL? Should I use it?

    ASIO4ALL is a generic "wrapper" that pretends to be an ASIO driver for devices that don't have one (like a laptop's built-in sound card). It should be a last resort. The native ASIO driver from your interface's manufacturer will always be more stable and have lower latency.

  • This is happening with my inputs too! My software only sees a stereo input.

    It's the exact same problem and solution. The default Windows "Recording Device" is often just a stereo pair. To get access to all 8 inputs (e.g., for "Live Input Cues" in SCS), you must install the manufacturer's ASIO driver and select it in your software. Your software will then see "ASIO In 1," "ASIO In 2," "ASIO In 3," etc.

  • My interface has a "Streaming Mode." What is that?

    Many modern interfaces have a physical button or a software setting that switches them between "Multi-Channel Mode" and "Stereo/Streaming Mode." Streaming mode mixes all your inputs down to a 2-channel stereo feed for simple applications like Zoom or basic OBS. Make sure this mode is turned OFF.

  • What audio interface should I get for live theatre productions?

    That's a great question, and having a reliable, multi-channel interface is key. For rock-solid performance with cueing software, we recommend looking at:


    • PreSonus STUDIO-1824C: A popular and robust rack-mount unit with plenty of I/O.
    • Focusrite Scarlett OctoPre: Known for its clean preamps and reliable drivers, it's a staple in many theatres.
    • Roland Octa-Capture: As you've seen in this article, it's a powerful and road-tested interface.
    • Bonus Multi-tasker: Allen & Heath CQ20T: This is a fantastic compact digital mixer that also functions as a powerful multi-channel USB interface. It's perfect for running your main show, and you can also grab it to run a lobby announcement or an outdoor pre-show event.

    We can get you great pricing on any of these. Before you check the big online stores, email us at yourfriends@techdirection.com—we're almost always able to beat their prices for our professional clients.

Bright Ideas for Outdoor Film Screenings and Theatre Off-Seasons: Portable 4K Projectors

November 3, 2025
The way we watch movies is changing. Audiences are increasingly skipping the traditional big-box cinema, looking for a unique experience without the sticky floors and high-priced junk food. This shift has sparked a boom in pop-up screenings, from outdoor film festivals and municipal "movie in the park" nights to live theatres using their off-seasons to generate new revenue. No matter the venue or the season, the challenge for all these groups is the same: sourcing projection that is portable, bright enough to compete with ambient light, and delivers the stunning 4K experience audiences now expect.

Announcing Tech Direction's Mission Impossible Award Winner!

October 16, 2025
This year's "Mission Impossible" Award goes to an individual who defied the odds, who stared down technical nightmares and emerged victorious. Their ingenuity transformed what seemed impossible into a breathtaking reality... 

Camera Techniques for Live Productions | By Tech Direction

August 7, 2025
Camera Techniques for Live Productions | By Tech Direction Are you passionate about videography and camera operation for live productions? Whether you're a camera operator, or a technical director, or simply curious about the art of camera operating, this session is designed for you. Watch on for an exclusive training session featuring a very special guest, Gio Benavidez. 
More Posts