USB Audio

Operation

Helix, Rack, LT, HX Stomp, and HX Stomp XL function as a USB 2.0, multiple-input/output, 24-bit-96kHz, low-latency audio interface for Windows and Mac computers, as well as for iPad or iPhone mobile devices (with optional Apple Camera Connection Kit adapter), and is compatible with all major DAW software.

NOTE

For USB audio operation:

For Windows computers, it is necessary to download and install the Line 6 Helix ASIO driver.

For Mac computers, it is only necessary to download and install the Line 6 Mac Core Audio driver if you desire audio sample rate operation at rates other than 48kHz.

For iPad or iPhone mobile devices, there is no driver installation necessary.

All drivers are available from line6.com/software. Please refer to the firmware Release Notes for driver support specific to the latest Windows and Mac operating systems.

With the default Input and Output block settings in use, you'll automatically hear audio software playback on USB 1/2 routed directly to the XLR (if applicable), 1/4" and Phones outputs. This lets you jam along with YouTube, iTunes, or your DAW tracks without hearing them through a bunch of amps and effects.

If you set your DAW software track to record from USB 1/2, you'll capture your processed input signal in the DAW track-with zero-latency monitoring, since you hear your input from the hardware outputs before it is routed through your software.

The additional USB Inputs and Outputs are available within the Input and Output blocks, and within your DAW software track menus. You can utilize these USB ins and outs for numerous routing configurations, all without patching extra cables-see the following examples.

Helix and Rack

Helix and Rack USB Example

Helix LT

Helix LT USB Example

HX Stomp, HX Stomp XL

HX Stomp USB Example

Hardware Monitoring vs. DAW Software Monitoring

Use of the default "Multi" settings for both the Input and Output blocks provides hardware monitoring, which allows you to hear your live input signal at all times, independent of your DAW software's monitor settings. Hardware monitoring can be desirable since it allows you to hear your live guitar with processing added and essentially "latency-free," since the monitor signal is not routed through your DAW software.

In some DAW recording scenarios, it may be preferable to utilize your recording application's "input monitoring" or "software monitoring" feature. This routes your live input signal through the armed recording track, thus allowing you to monitor the input effected by any plugins you may have inserted on the track. However, the one downside of DAW software monitoring is that your live input signal is delayed slightly due to being routed through the software and back to the outputs. This is referred to as "latency." Helix, Rack, LT, HX Stomp, and HX Stomp XL are designed to provide very low latency operation-see "ASIO Driver Settings (Windows)" for info and settings.

Helix, Rack, LT

When a DAW track's software monitoring is active, you'll likely not want to hear the hardware monitoring signal simultaneously. To achieve this, you can set the Output block to USB Out 3/4 or 5/6. These Output block options will route your processed, stereo signal out to your DAW software without also providing the hardware monitoring to USB 1/2. You'll then need to set your DAW track to receive from the same selected USB Out to record the processed signal into the track - or, you can optionally set the DAW track input to USB 7 or USB 8 to record a dry DI signal-see the next section.

HX Stomp, HX Stomp XL

When a DAW track's software monitoring is active, you'll likely not want to hear the device's hardware monitoring signal simultaneously. To achieve this, it is best to use the device's USB 5/6 inputs as your DAW audio track's input source and select the Main L/R Output block on the device's and turn its Level all the way down. This configuration allows you to hear and record only the dry, DI signal from the device into your audio track. (See the next section for more on recording a DI track.)

DI Recording and Re-amplification

A common DAW recording technique is to record a dry DI (Direct Input) signal, such as the unprocessed signal from your guitar, Variax, or mic, along with your mic'ed or processed tone. This allows you to process the DI track later with plugins (such as the Line 6 Helix Native plugin) and/or "re-amplify" the DI track through an amp or other outboard gear. Helix, Rack, LT, HX Stomp, and HX Stomp XL have handy options built right in for recording DI tracks, as well as for easy re-amplification of DI tracks back through your own tones, all without extra hardware or cabling!

Helix, Rack, LT

Helix, Rack, and LT offers two special DI outputs, USB Outs 7 and 8, which appear as available options within your DAW software track input menus. These two dedicated USB Outs are tapped directly from the Helix input sources of your choice. To configure the Helix input source for each, go to Global Settings > Ins/Outs > Re-amp Src (USB 7) and Re-amp Src (USB 8), where you can select Guitar, Aux, Variax, Variax Mags, or Mic (where applicable).

Recording a Dry DI Track

For this example, we'll record guitar into two DAW tracks simultaneously, with one capturing the Helix-processed tone and the other the unprocessed DI guitar.

  1. In the Global Settings > Ins/Outs > Page 3 (page 2 for LT) screen, set Re-amp Src (USB 7) to "Guitar".
  2. Dial in your desired tone, while keeping the Input and Output blocks both set to the default "Multi" setting.
  3. Create two new audio tracks in your DAW software project:
  • Create one mono track to record the dry DI guitar, and set the track's input to USB 7.
  • Create one stereo track to record your full, stereo-processed tone and set the track's input to USB 1/2.
Recording a Dry DI Track
  1. Set both tracks' outputs, as well as the DAW Master output, to USB 1/2 to allow all tracks to play back through Helix, Rack, or LT.

Note

Setting the stereo track's output to USB 1/2 allows you to hear your processed tone via hardware monitoring while recording. For this configuration, disable software monitoring on all DAW tracks.

  1. Arm both these DAW audio tracks, hit the Record button and start laying down your guitar performance!

Now you have your processed track to hear with the project and a separate DI track with which you can further experiment at any time with DAW plugins and/or re-amping.

Re-amping

If your DAW software provides options for routing individual audio tracks to outputs other than just the main USB Out 1/2, then you can use these steps for re-amping a dry recorded DI track back through Helix, Rack, or LT.

  1. In your DAW software, set the DI track's Output setting to a stereo USB Out other than USB Out 1/2. For this example we'll use USB Out 3/4.

  2. Create a new stereo track in your DAW project and set this track's Input and Output both to USB 1/2 - Let's name this track "Re-amped." Arm the track for recording.

Note

In some DAW software, it may be necessary to also activate the software monitoring feature on this "re-amped" track to monitor the processed signal when playing back your project. See your software's documentation.

  1. On Helix, Rack, or LT, select the Input block and set it to receive from the same USB stereo pair (USB In 3/4) and keep the Output block set to "Multi." Load your choice of amps and effects on the current Helix preset.
Re-amping
  1. Now play your DAW project and you'll hear the DI track "re-amped" through your Helix, Rack, or LT! Adjust the DI track's volume slider to make sure the signal feeding into Helix, Rack, or LT is not too hot. Tweak your amp & effects as desired while listening with the playback of your project mix.

  2. Once you have your re-amplified guitar tone they way you like it, Solo both the DI and re-amped tracks, rewind to the start of the project and hit the DAW Record button, allowing it to capture the signal into the new re-amped track in real-time.

Allow the DI track to play to the end, stop recording, and you've created your new re-amped guitar track!

Tip

Note that you still have your original Guitar DI track, and you can repeat this process to create additional re-amped tracks with different settings, add plugins, blend with your original guitar track, and more.

HX Stomp, HX Stomp XL

HX Stomp and HX Stomp XL offer two special DI outputs-USB Outs 5 and 6, which are fed directly from the Main L/MONO and RIGHT inputs. Also, note that USB Outs 7 and 8 are fed directly (unprocessed) from the Return/Aux In L/MONO and RIGHT inputs for simultaneously tracking a stereo digital piano, synth, drum machine, or other device.

Recording a Dry DI Track

For this example, we'll record guitar into two DAW tracks simultaneously, with one capturing the processed tone and the other the unprocessed DI guitar.

Recording a Dry DI Track
  1. Create two new audio tracks in your DAW software project:
  • Create one mono track to record the dry DI guitar, and set the track's input to the device's USB 5.
  • Create one stereo track to record your full, stereo, processed tone and set the track's input to the device's USB 1/2.
  1. Set both tracks' outputs, as well as the DAW Master output to the device's USB 1/2 to allow all tracks to play back through the device.

Note

Setting the stereo track's output to the device's USB 1/2 allows you to hear your processed tone via the device's hardware monitoring while recording. For this configuration, disable software input monitoring on all DAW tracks.

  1. Arm both these DAW audio tracks, hit the Record button and start laying down your guitar performance!

Now you have your processed track to hear with the project and a separate DI track with which you can further experiment at any time with DAW plugins and/or re-amping (see the next section).

Re-amping Through HX Stomp or HX Stomp XL

Now let's take the dry DI guitar track we recorded and route it back through the device for processing.

Re-amping
  1. From Play view, turn the Upper Knob to select the Input block and then turn the Lower Knob to choose "Input USB 5/6."

You'll see that a small USB icon has replaced the Input block (also see "Signal Present and Clip Indicators"):

Icon change
  1. In your DAW software, set the DI track's Output setting to the device's USB 5/6.
  2. Create a new stereo track in your DAW project and set both its Input and Output to USB 1/2. Arm the track for recording.

Note

In some DAW software, it may be necessary to also activate the software monitoring feature on this "re-amped" track to monitor the processed signal when playing back your project. See your software's documentation.

  1. Now play your DAW project and you'll hear the DI track "re-amped" through the device! Tweak your amp & effects blocks as desired while listening with the playback of your project mix.
  2. Once you have your re-amplified guitar tone they way you like it, Solo both the DI and re-amped tracks, rewind to the start of the project and hit the DAW Record button, allowing it to capture the signal into the new re-amped track in real-time.

Allow the DI track to play to the end, stop recording, and you've created your new re- amped guitar track!

Tip

Note that you still have your original Guitar DI track, and you can repeat this process to create additional re-amped tracks with different device settings, add plugins, blend with your original guitar track, and more.

Core Audio Driver Settings (macOS)

To use Helix, Rack, LT, HX Stomp, or HX Stomp XL as an audio interface for Mac applications, it is not necessary to install any additional driver. The device will automatically utilize the Mac computer's "Class Compliant" USB driver when connected to your USB port. The hardware will then appear as a selectable Core Audio device within the Mac Utilities > Audio MIDI Setup panel and/or directly within your audio and multimedia applications.

The Apple Class Compliant driver offers strictly 48kHz native sample rate operation. If you prefer to use a different native sample rate (or if your particular DAW application requires it), you can optionally download and install the Line 6 Mac Core Audio driver from line6.com/software. This Line 6 driver offers 44.1kHz, 48kHz, 88kHz, or 96kHz sample rate operation.

ASIO Driver Settings (Windows)

When using Helix, Rack, LT, HX Stomp, or HX Stomp XL as an audio interface for Windows DAW applications, it is highly recommended to configure the software to utilize the “ASIO” driver. The Line 6 ASIO driver offers the superior, low-latency audio performance required for DAW recording. This driver selection is typically found in your DAW software’s Preferences or Options dialog - see your software’s documentation.

Note

Download and install the latest Line 6 Helix ASIO driver from line6.com/software.

Once the ASIO driver has been selected in your DAW software, you’ll also see a button in the same dialog for “ASIO Settings” (or with a similar title). Press this button to launch a Control Panel, where you make the following driver settings.

ASIO setting
SettingDescription
Sound Control PanelThis button launches the Windows Sound Control Panel, which is where you can optionally configure Helix, Rack, LT, HX Stomp, HX Stomp XL to be the audio playback device for multimedia applications (such as Windows Media Player, iTunes, etc.) These settings are not relevant for your DAW software since these applications utilize the standard Windows driver.
Default Bit DepthSelect the Bit Depth at which Helix, Rack, LT, HX Stomp, or HX Stomp XL will operate for recording and playback with your DAW software. 24 bit or 32 bit are recommended for quality audio production.
ASIO Buffer SizeYour goal is to achieve the lowest latency possible in your DAW software, but with glitch-free audio performance. Smaller buffer size results in lower latency, however, also increases the demands on your computer, which can result in clicks, pops, or other audio artifacts. Start with a lower slider setting here and if you encounter audio performance issues, come back to this panel and move this slider to the right incrementally to remedy the problem.

Click the Apply and OK buttons when your Control Panel settings are complete to return to your DAW software. Please also refer to your DAW software’s documentation for more about its own specific audio device, buffer, and project settings.

Last updated: March 7, 2021