Once the Starter Kit hardware has been set up and verified using the Starter Kit Utility diagnostics, it can interact with the Global Tuning Tool (GTT), a Windows Application for designing audio processing pipelines and signal flows, flashing them on target amplifiers (in our case, it is the Starter Kit) and tuning the Audio Objects (AO) in the signal flows in real-time.
GTT includes a sample project for the AudioworX Starter Kit that can be used a starting point for users to get familiar with the Starter Kit.
The example project for the AudioworX Starter Kit implements a simple signal flow, a custom tuning panel and some presets to showcase common AudioworX workflows that are explained in the Global Tuning Tool User Guide.
The following sections guide first-time users through the initial setup of AudioworX using the Starter Kit.
- Importing The Example Project
- Configuring AmpSrv2 Settings
- Sending the Device Configuration to the AudioworX Starter Kit
- Connecting to the Starter Kit for Tuning
- Tuning the Audio Processing Pipeline
- Saving and Recalling Tunings using Parameter Sets
- Managing Presets using the Preset Controller
The Home Screen of GTT provides options such as importing a project, creating a new project, open an existing project, explore some high-level features of GTT, etc. For more details, refer Home screen options page.
To open the Starter Kit example project:
- Go to the Sample Projects tab.
- Double click the “AWXExampleProjectStarterKit” project.
- GTT may display a warning message. This warning is due to the project being similar to the default example project of GTT. Click “No” and proceed.
This opens the Device Designer window. The Device Designer is the first view of GTT that is shown on opening a GTT project. This tab shows a high-level view of the audio processing pipeline, showing the audio system/device and its abstractions as shown in the below figure.
- The Device level abstraction (AWXExampleProject1): This represents the actual physical device or the target device with physical audio inputs and outputs. The Starter Kit can have up to 2 audio input channels and 8 audio output channels which are provided by the Creative Sound Blaster X4 audio interfact. These channels are highlighted as “Physical Audio Inputs/Outputs” in the above image.
- The Physical core (arm64-v8a): This block represents the Digital Signal Processor (DSP) core that performs the audio processing. Although the Raspberry Pi 5 contains 4 64-bit Arm v8a Cores, currently, only one of the cores is supported for performing audio processing operations by the AudioworX Amp Application in the Starter Kit. Other AudioworX amplifiers may have more than one DSP core, each of which will be represented separately in the device designed view.
- The Virtual Core (Entertainment Task): This block represents a single virtual core performing a specific audio task. A virtual core processes audio at a user defined sample rate and block length, which can be configured in the “Edit Device” menu at the bottom of the “Device Designer” tab (also explained in Create Device File).
In this example, we have one virtual core that takes a stereo audio input and gives out a 7.1 channel output (8 channels in total). This block is populated with core objects that can be dragged-and-dropped from the “Toolbox” pane on the left-side of the “Device Designer” view and interfaced together to perform operations such as sample rate conversion, buffering, routing, that may be required by the main audio processing instances called the “Xaf Instance”.
For Core Objects Toolbox details, refer Core Objects Toolbox. A physical core may have more than one virtual core, each of which will be handled by a separate OS thread. - The Audio Processing Instance (Xaf Instance): This block represents the core of the audio processing pipeline which is designed using the Signal flow Designer tool to implement a signal flow (Refer to Xaf Instance).
The rest of the Starter Kit documentation only briefly explains concepts that are relevant to a first-time user in the context of the AudioworX Starter Kit.
The Starter Kit is pre-configured with all the necessary data files to run the example project on first boot. The user may skip to the Connecting to the AudioworX Starter Kit for Tuning section for instructions on connecting to the Starter Kit. However, the following sections highlight some important steps that are specific to the Starter Kit for educational purposes before getting started with tuning of the signal flow itself.
The project’s AmpSrv2 settings must be configured for GTT to be able to communicate with the Starter Kit hardware for operations such as sending the audio processing signal flow and tuning.
Steps to configure AmpSrv2 settings:
- On the Device Designer tab, click on AmpSrv Settings on the top ribbon bar and click Configure.
- In the AmpSrv window, go to File > Options > Socket, and set the hostname to “raspberrypi.local” and the port to “25001”.
- Click Ok to close the AmpSrv2 settings window and minimize the AmpSrv2 window.
- On the Device Designer tab, click on AmpSrv Settings and click on Save from the drop-down menu to save the settings.
For AmpSrv2 Settings details, refer to the Connection page.
Sending the Device Configuration to the AudioworX Starter Kit
The device configuration contains information on how the physical and virtual cores, the Xaf instances (which contain the core of the signal processing flows) and other core AOs are interconnected to form the audio processing pipeline. As previously mentioned, the Starter Kit is pre-configured with the required data files, which includes the device configuration to run the example project on first boot.
For a different project or if any changes have been made to the example project, it is important to send the device configuration to the Starter Kit, to ensure the AudioworX Amp application can set up and execute the audio processing pipeline.
Steps to send the device configuration defined in the GTT project to the Starter Kit hardware:
- On the Device Designer tab, click on Send Device Config.
- Once the device configuration is sent successfully, if the new device configuration is different from the previously flashed device configuration on the Starter Kit, GTT may prompt the user to reboot the device.
- In such cases, the AudioworX Amp application running in the Raspberry Pi 5 must be reset using the Starter Kit Utility tool by running the command:
python3 SKUtility.py rmt -rst
This command is explained under Reset AudioworX Amp Application in SKUtility Remote Control. For other AudioworX based amplifiers, a full reboot may be required.
Connecting to the AudioworX Starter Kit for Tuning
Once the device configuration has been sent to the Starter Kit hardware and the AudioworX Amp application has been reset (only required if prompted by GTT), the Starter Kit can be connected to from GTT for tuning.
Steps to connect GTT to the AudioworX Starter Kit:
- Click the Connect Device button located in the top ribbon bar to initiate device connection.
- A “Device Synchronization” window will pop up. Click on the Send button to send the tuning data.
- Once the data has been sent and the device has been connected, the audio processing pipeline and its signal flow can be tuned in real-time.
- To stop tuning and disconnect the Starter Kit from GTT, click the Disconnect Device button in the top ribbon bar of the Device Designer tab.
Tuning the Audio Processing Pipeline
The audio processing pipeline can be tuned in two ways: using the State Variables button in the top ribbon bar or by using a custom panel.
Tuning using State Variables
The State Variables explorer can be accessed from the top ribbon bar in the “Device Designer” tab as shown below.
The rows in the State Variable explorer such as “Gain_1_0_0”, “Limiter_1_0_0”, etc., correspond to the names of the specific AOs in the signal flow. Expanding the row items in the tree display the tunable parameters of the AOs can be set in the right-half of the window as show in the above figure.
Tuning using the Custom Panel
GTT provides the capability to design a custom User Interface specific to the signal flow in the project using drag-and-drop methodology, allowing the user to define their own tuning interface with simple steps from the “Panel Designer” tab. For details on custom panel creation and usage, refer Create a Custom Panel in GTT.
The example project includes a custom tuning panel that is pre-designed for tuning the audio processing pipeline by exposing essential tuning parameters for the AOs in the signal flow.
To launch the custom panel, go to the “Panel Designer” tab and double-click the item named “ExampleProject1” in the “Panels” pane on the left-hand side of the view as shown below.
This custom panel window has three tabs, each tab is tailored to facilitate tuning of audio parameters at different levels of detail.
- Main
- Mute/Gain/Inv
- SignalFlow
Main: The “Main” tab provides users with high-level volume and mute controls along with a global Bass and Treble control. The below image shows the “Main” tab of the Custom Panel.
Mute/Gain/Inv: The second tab is the “Mute/Gain/Inv” tab, which provides users with volume and mute controls for each of the 8 output channels in the audio processing pipeline, along with polarity controls for each speaker to minimize effects of phase destruction in the listening environment. The below image shows this tab of the Custom Panel.
SignalFlow: The “SignalFlow” tab, which provides more granular control of the overall signal flow, exposing controls such as individual speaker delays, EQ, limiter, noise gate, etc., which can be opened by clicking the individual blocks in the signal flow. The below image shows this tab of the Custom Panel.
Saving and Recalling Tunings using Parameter Sets
GTT allows users to save and recall tunings as presets from the “Parameter Sets” tab of GTT.
In the Starter Kit example project, 2 presets are created, namely “LFHighOnly” and “AllSpeakers”, where the first one mutes all speakers except for the Left-Front High speaker and the second preset enables audio outputs from all speakers.
For detailed information on the Parameter Sets tab and its features, refer to Parameter Set Overview.
Saving Custom Tunings
To save a tuning that you’ve made using the State Variables explorer or the custom panel, follow below steps:
- Go to the Parameter Sets tab.
- Click the New button on the top ribbon bar. This will create a new column named “Set3”.
- Right-click the new column and select Retrieve to populate it with the current tuning settings.
To overwrite a preset, right-click the preset column and click Retrieve. Once the preset has been written, it is automatically saved with the project.
In the example project, the presets (described above) store all tuning parameters in the signal flow. However, they can be customized to store only a sub-set of all the tuning parameters in the signal flow using “Set Group” (left-side pane in the “Parameter Sets” view).
For details on creating a new set group with a sub-set of tuning parameters, refer to Create a Parameter Set in GTT.
Applying Tunings from a Saved Preset
A preset can be applied to the target by right clicking the preset name and clicking the Apply button as shown below:
Applying a preset sets the tuning parameters in a live signal flow running in a target device (here it is the Starter Kit), only if the device is connected. If the target device (here, the Starter Kit hardware) is not connected to the GTT session, only the local states of the parameters within GTT will be updated, which then needs to be sent while connecting the device as described in Connecting to the AudioworX Starter Kit for Tuning.
Managing Presets using the Preset Controller
GTT provides a method for recalling and managing presets using data files stored in the target device’s flash memory using the “Preset Controller”, which is accessible from the “Device Designer” tab of GTT as shown below.
Presets made in the “Parameter Sets” tab can be mapped to slots in the “Preset Controller”, which represent preset files on the target device, for quick recall of presets.
In the Starter Kit example GTT project, there are 2 pre-made preset slots; “LFHighOnly” and “Allspeakers” (slots 1 and 2 respectively), which are mapped to the “LFHighOnly” and “AllSpeakers” presets in the “Parameter Sets” tab mentioned earlier.
The “Preset Controller” can be used to set presets by selecting the required Slot ID and clicking the “Load Slot” button at the bottom of the window. A default slot can also be selected to load on boot-up using the “Default Slot” drop-down menu. In the Starter Kit example project, the “AllSpeakers” preset is made as default.
For details on configuring the Preset Controller, refer to Configuring Preset Controller.