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Using Quad Cortex as an audio interface

Quad Cortex doubles as a USB 2.0, 24-bit, fixed 48kHz, ultra-low latency audio interface for Windows® and Mac® computers.

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Overview

Quad Cortex doubles as a USB 2.0, 24-bit, fixed 48kHz, ultra-low latency audio interface for Windows® and Mac® computers.

It features 4 hardware inputs, 6 hardware outputs, and 8 digital inputs / outputs via USB. The Quad Cortex is also compatible with all major DAWs.

This makes it an ideal all-in-one solution for processing and recording not only guitar and bass tones, but also vocals and a variety of other instruments.

When you use the Quad Cortex as an audio interface, the Cortex Control desktop controller allows you to easily control and adjust the settings of your Quad Cortex on your computer.

    Setting up your Quad Cortex as an audio interface

    macOS setup

    Step 1: Use the USB Type-B cable included in the box to connect your Quad Cortex to your computer. No additional drivers are needed. After connecting, you’ll be able to use your Quad Cortex as an audio input and output device.

    Step 2: Go to System Preferences > Sound, and set Quad Cortex as the Output and Input device.

    Windows setup

    To use the Quad Cortex as a USB audio device on Windows computers, you’ll first need to download and install the Quad Cortex ASIO driver from our website.

    Step 1: Download the driver installer from our Downloads page.

    Step 2: Run the installer and follow the on-screen instructions.

    Step 3: After installing the driver, use the USB Type-B cable included in the box to connect your Quad Cortex to your computer.

    Step 4: Go to Control Panel > Hardware and Sound > Sound and make sure your Quad Cortex is set as the Default Device in both the Playback and Recording tabs:

    • Playback tab: The Quad Cortex has multiple outputs. Select the outputs your monitoring devices are connected to as the Default Device. For example, if you have connected your studio monitors to outputs 3 and 4, select Quad Cortex (3+4) as your default playback device.  Afterwards, right click the device and select Properties. Go to the Advanced tab and make sure the Default Format is “2 channel, 24 bit, 48000 Hz (Studio Quality)”.

    • Recording tab: Select Quad Cortex (1+2) as your default recording device. Afterwards, right click the device and select Properties. Go to the Advanced tab and make sure the Default Format is “2 channel, 24 bit, 48000 Hz (Studio Quality)”.

    Important: For optimal performance, connect the Quad Cortex directly to your computer's motherboard USB ports (USB 2.0 or higher). Please refrain from using USB hubs or front panel USB ports on PC cases.

    Monitoring

    Outputs 1/2, 3/4, and the headphones output can be used for plugging in monitoring devices such as studio monitors and headphones.

    When your Quad Cortex is selected as the audio device on your computer, you will hear your computer audio through the Quad Cortex outputs you selected as the output device and through the headphones output. This lets you play along with backing tracks on YouTube™ or with your DAW tracks with ultra-low latency monitoring.

    You can use multiple outputs by tapping the Output block on the right-hand side of The Grid. The Multi-Out block routes your signal through outputs 1/2 and 3/4, and USB. All Factory Presets and newly created Presets use the Multiple Outputs block.

    Use the Volume knob on your Quad Cortex to control the output volume of all the outputs.

    You can independently control the output levels of specific outputs in the I/O Settings menu. 

    DAW routing and recording

    Recording your processed signal, dry input, or specific rows from The Grid is a breeze with Quad Cortex’s flexible routing settings.

    Additionally, you will hear your signal directly from Quad Cortex before it’s routed through your DAW, resulting in ultra-low latency monitoring.

    Thus, there is no need for monitoring through your DAW, so make sure to turn off input monitoring on your audio tracks in your DAW.

    When recording, also make sure that your Quad Cortex is the main audio device in your DAW settings.

    Recording your processed signal

    Step 1: Plug your instrument to INPUT 1.

    Step 2: Open your DAW and create a stereo audio track and set its input to Input 3/4.

    Step 3: Arm the track for recording and press record.

    Recording your DI signal

    Step 1: Plug your instrument to INPUT 1.

    Step 2: Open your DAW and create a mono audio track and set its input to Input 1.

    Step 3: Arm the track for recording and press record.

    Note: You can choose whether the DI or processed signal is fed into outputs 1/2 or 3/4. To change the settings, open the I/O Settings menu, tap USB, go to the second settings page, and toggle the DRY - WET switch.

    Recording your processed signal and DI signal simultaneously

    Step 1: Plug your instrument to INPUT 1.

    Step 2: Open your DAW and create a stereo audio track and set its input to Input 3/4. This track will capture your processed signal.

    Step 3: Open your DAW and create a mono audio track and set its input to Input 1. This track will capture your DI signal.

    Step 4: Arm both tracks for recording and press record.

    Reamping a DI track

    Reamping a DI track means sending a DI recording from your DAW back through the Quad Cortex. This lets you apply amp models and effects to the track to explore different tonal possibilities without having to re-record the part.

    Send your DI track through the Quad Cortex

    Step 1: In your DAW, go to your DI track's output routing settings and select Output 5 as its output:

    • Logic Pro X: Use the track’s output routing options in the mixer.

    • Ableton Live: Select Output 5 from the track’s 'Audio To' dropdown in the Session view.

    • Pro Tools: Use the I/O setup to assign your DI track's output.

    • Reaper: Use the route button on the track to set the output.

    • Cubase: Use the routing section in the inspector or the MixConsole.

    • FL Studio: Use the mixer channel’s output selector.

    If needed, refer to your DAW's manual for detailed instructions on routing.

    Step 2: On your Quad Cortex, change your input block to USB input 5 on The Grid.

    Step 3: Press play on your DAW to play the DI track through your Quad Cortex.

    C) Recording the reamped signal

    Step 1: Create a stereo audio track and set its input to Input 3/4.

    Step 2: Arm the track for recording and press record (making sure your DI track isn’t also armed for recording).

    USB I/O schematic

    Quad Cortex features 16 USB channels (8 in / 8 out). Each of these channels are specifically mapped or assigned to different audio sources or connectors on the Quad Cortex.

    This mapping determines where the audio comes from (for inputs) and where it goes to (for outputs) when using Quad Cortex as an audio interface:

    Using Quad Cortex as an audio interface with Neural DSP plugins

    In order to use Neural DSP plugins with Quad Cortex as your audio interface, you will need to remove the input from The Grid. This prevents the Quad Cortex from outputting its own audio when you're using the plugins.

    Step 1: In The Grid, tap the Input Block and select Not In Use.

    Note: To streamline the process, you can create and save an empty preset that has no input  set. This can be quickly loaded whenever you use the standalone versions of Neural DSP plugins.

    Alternatively, simply engage the TUNER on the Quad Cortex to mute The Grid.

    Using the standalone versions of Neural DSP plugins

    Step 1: Launch the standalone version of your Neural DSP plugin and open the settings menu.

    Step 2: Use the following audio device settings:

    macOS:

    • Audio Device Type: CoreAudio

    • Audio Input Device: Quad Cortex

    • Audio Output Device: Quad Cortex

    Windows

    • Audio Device Type: ASIO

    • Audio Input Device: NeuralDSP USB Audio Device

    Step 3: Configure the remaining settings:

    • Audio Input Channels: Select the Quad Cortex input your instrument is plugged into. Make sure to disable all the inputs you're not using.

    • Audio Output Channels: Select the output channels that your monitoring device(s) are connected to.

    • Sample rate: 48000 Hz

    • Audio Buffer Size: Set it to 128 samples or lower.

    Loading Neural DSP plugins in a DAW

    Step 1: Make sure Quad Cortex is set as your audio device in your DAW settings.

    Step 2: Create an audio track and set its input to Input 1. Make sure input monitoring is turned on.

    Step 3: Load a Neural DSP plugin to the track. For more detailed instructions, refer to our guide on loading plugins in your DAW.

    Connecting Quad Cortex to an iPhone® or iPad®

    Quad Cortex can be used as an audio interface with iPhones® and iPads®, allowing you to directly record your playing on apps like GarageBand®.

    To connect your Quad Cortex to an iPhone® or iPad®, you will need an Apple® Lightning to USB-3 Camera Adapter.

    If your iPhone® or iPad is equipped with USB-C or Thunderbolt 3, a USB-C to USB Adapter is required instead.

    Step 1: Use the appropriate adapter to connect your Quad Cortex to your iPhone® or iPad®.

    Step 2: You can now use your Quad Cortex as the main audio device for your iPhone® or iPad.

    MIDI over USB

    Quad Cortex can receive and send MIDI messages over USB. This lets you automate tone and preset changes within your DAW, use the footswitches to trigger backing tracks, or use your Quad Cortex to send MIDI messages to external devices.

    Automation allows you to focus entirely on your performance rather than having to manually engage footswitches during key moments.

    Note: In order to receive MIDI messages from DAWs, make sure Quad Cortex is enabled for sending and receiving MIDI messages in your DAW’s MIDI device settings.

    MIDI Settings menu

    Tap the Main Menu on The Grid and select Settings to access the MIDI Settings menu.

    MIDI Channel: Tap to choose the MIDI channel (1-16) Quad Cortex will use.

    MIDI Thru: Tap to enable/disable the MIDI Thru feature. MIDI Thru allows Quad Cotex and other devices to have their MIDI connections “daisy chained” together all being driven by a common MIDI source.

    MIDI over USB: Tap to enable/disable the MIDI communication via USB.

    Ignore Duplicate PC: When enabled, the current active Preset will not be reloaded if its corresponding MIDI PC message is sent to Quad Cortex. CC#0 and CC#32 messages will also be ignored. When disabled, the current active Preset will be reloaded if its corresponding MIDI PC message is sent to Quad Cortex.

    MIDI Clock Out: Tap to enable/disable MIDI clock out for USB or DIN outputs. Note that MIDI OVER USB must be set to “ON” to enable MIDI clock out over USB.

    Receiving MIDI Program Change (PC) messages to change Presets

    Quad Cortex uses MIDI PC messages to change Presets and Setlists.

    CC#32 is used for changing Setlists, supporting up to 12 Setlists (value 0-12).

    CC#0 is used for splitting up the Setlists into groups of 128 Presets. Value 0 is used for Presets 0-127 and value 1 is used for Presets 128-256.

    Example 1

    To load Preset 17A in Setlist 5, you would send the following PC message to the unit:

    • CC#0 value 1, CC#32 value 5, Program #0

    Example 2

    To load Preset 9D in Setlist 9, you would send the following PC message to the unit:

    • CC#0 value 0, CC#32 value 9, Program #67

    Use this tool to quickly determine what PC message should be sent to load specific Presets within your Setlists.

    In Cortex Control, you can press CMD + Shift + M on Mac or Control + Shift + M on Windows to display the MIDI program change message for the preset that is currently loaded.

    MIDI Continuous Controller (CC) messages for controlling global functions

    You can control global functions on your Quad Cortex with the following MIDI CC messages:

    MIDI Continuous Controller (CC) messages for controlling Looper X functions

    You can control Looper X functions on your Quad Cortex with the following MIDI CC messages:

    Preset MIDI Out settings

    Quad Cortex can send MIDI messages to external devices. These messages can be mapped and modified in the Preset MIDI Out menu.

    Tap on the Footswitches or Expression Pedals in the settings interface to map MIDI messages.

    ON PRESET LOAD MESSAGE Module: Tap to set up to 12 MIDI messages that will be sent simultaneously once the current Preset is loaded.

    A-H Footswitches: Tap to assign up to 12 MIDI messages per footswitch. Once assigned, you can modify their Type, Channel, and Program values.

    1 & 2 Expression Pedals: Tap to assign up to 4 CC MIDI messages per pedal. Once assigned, you can modify their Channel, CC#, and Program values.

    FAQs and common issues

    Is the Quad Cortex compatible with all major DAWs?

    Yes, it is compatible with all major DAWs. However, you may need to adjust settings based on the specific DAW you're using.

    How can I reduce headphone hum when using the Quad Cortex?

    If you experience humming or noise in your headphones, try adjusting the headphone level and mix settings. In the I/O Settings menu, tap the headphone output and reduce the HP LEVEL to -5dB, compensating with the Volume Wheel. Reduce further if there's still a hum or other unwanted noise.

    Robotic or distorted sounds on playback

    First, try rebooting your Quad Cortex. Ensure you're running the latest CorOS version. Increasing the buffer size may help resolve the issue.

    For Windows users, ensure the latest NDSP ASIO driver is installed. Switching to safe mode within the NDSP ASIO settings might resolve the issue.

    Finally, ensure your DAW's sample rate matches the Quad Cortex's rate (48kHz).

    What should I do if I encounter persistent issues?

    If you continue to have problems despite troubleshooting, contact Neural DSP support at support@neuraldsp.com for further assistance.

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