Category: SignalFlowDesign

This feature enables signal flow designer to group multiple control signals into a block control.

Audio objects needed or block control signal to control signal conversion and vice-versa.

• Control Grouper: Facilitates SFD user to group the control signals into block control.
• Control Splitter: Facilitate SFD user to split the individual control signals.

Any audio object which supports block control should declare a flag in dynamic metadata as below.

The block control connections are highlighted as thick lines in both SFD and CAO signal flows.

Block control pins are in dark orange color and on connection mouse hover block pin details are displayed.

It is possible to make block connections only when the group count matches. Else a validation error will be thrown.

If the group count is 1, it is possible to connect normal control pin with block control pin.

When linked to an object, the Smart LUT feature automates the process of adding column labels semi-automatically rather than manually.

The “Open column name Configuration Panel” feature only supports LUT audio object.

Launching Column Name Panel

You can use this feature to choose which state variable values should be shown as column headers on the LUT panel. To begin assigning state variables to the columns of the LUT panel, simply open the panel by accessing the context menu of the LUT object in the SFD.

SFD must be saved before opening this feature else the state variables will not be available.

Following are the components available on Column Naming Window.

1. Tree with all objects
2. List with columns details

State variables associated to different objects

State variables can be filtered in two ways:

By clicking on the individual audio objects in the tree – each click will display the state variable of the respective audio object. Multiple objects can be selected to display their state variables.

Or

Use the Search bar and type required text, for example AO name (not case sensitive).

Selecting State Variable

Each state variable can be assigned to only one column. After assigning to column, it will disappear from available state variables.

To assign state variables to a column, select the state variable and drag it to the appropriate column.

• To Select: Multiple state variables can be selected by holding the CTRL key or by clicking the ‘Select all’ button above.
• To Move: For moving selected variables, use the SHIFT key to hold and move the variables.

When all columns are completed, the ‘Apply’ button in the bottom right corner will become active. It will also be enabled if all columns are empty.

To stop using state variables for naming it is necessary to open the Naming panel, clear all variables and apply.

Workaround for LUT Parameter Sets Unit Problem

This workaround is required for projects which are exported earlier than N+1 release.

1. Import earlier exported project and open Signal Flow designer.
   • If all LUT objects belong to the same group, double-click on any LUT objects to launch the panel.
   • If each LUT object belongs to different groups, then launch the panels separately for each group.
2. Close the LUT panels.
3. Open Parameter sets view, right-click on column header of red color highlighted set, and click ‘Store’ context menu to get latest set values.
   You can observe the red highlights are cleared and units are removed for each state variable.

When you launch signal flow designer by double-clicking on the Framework Instance in device view, GTT validates all audio objects that are mismatching with the toolbox. A report is displayed with the version difference of all audio objects, with the option to auto-upgrade them based on the user’s preferences.

If you select “Yes”, all audio objects will automatically be upgraded to the version equivalent to the toolbox version. If any compound audio objects exist. They must be upgraded manually.
If you select “No”, the signal flow will be launched and you need to manually upgrade them.

If the audio object in the signal flow design becomes out of sync as a result of modification. The compiler report will display a warning message, and the audio objects will be highlighted in blue.

To manually upgrade the audio object to the signal flow designer state; right-click on the highlighted audio object and select “Upgrade Audio Object” from the context menu.

Until N-release, if any audio objects are out of sync with the audio library, GTT will not allow you to save or send the signal flow to a device. To pass the validation, you must manually replace (delete) the current audio objects in the signal flow with the toolbox audio object. All connections and tuning data are lost during this process, which must be redone, resulting in increased effort.

The below image shows the context menu option to choose “Upgrade Audio Object”. When the audio object is upgraded, there will be messages to guide you to the next steps.

The following audio object properties will be upgraded:

• Additional variables (added or deleted)
• Modes (added or deleted)
• Audio object properties like input/output, channels, etc
• Tuning version

The audio objects with major tuning version changes or structural changes, such as additional variable changes, will be detected as incompatible and highlighted in blue. Until all these incompatible AOs are upgraded, signal flow cannot be saved.

Version changes in Tuning will be highlighted in blue and Until all these AOs are upgraded, signal flow cannot be saved.
Tuning data and Parameter sets will be preserved incase of a Minor version change while incase of a Major version it will not retain data

Example: When the tuning version of an audio object in the signal flow is 04.00 and the version in the toolbox is 04.01, only the minor version has changed. As a result, the tuning data will be saved.
Similarly, if the tuning version of an audio object in the signal flow is 04.00 and the toolbox version is 05.00, tuning data will be lost because the internal structure of the AO has changed.
When the upgrade is complete, a message will appear informing the user of the tuning data status.

The above message is a warning that there may be a tuning data loss because the audio library changed the major version in the tuning version. The set group(s) to be modified will be listed in the message.
If no set groups are created using the respective audio object, the following message will be shown.

Upgrade Compound Audio Object (CAO)

The compound audio object (CAO) in the signal flow can also be upgraded. For minor version changes, only the version number will be updated, but no other changes will be made. However, in the case of a major version change in the toolbox, the internal audio object will be updated to the latest version according to the CAO type in the toolbox.
If there is a major version change and the inner objects cannot be automatically upgraded, the CAO will be marked with a blue color and then you need to upgrade the CAO.

For more details about the compound audio object, refer to the Compound audio object.

To upgrade the Compound audio object, follow the below steps:

1. On the Signal Flow Designer window, select the compound audio object under the Compound Audio Object category in the toolbox and click Edit through the context menu. This opens the Compound Audio Object editor, where you can view the signal flow of the internal audio objects.
   
2. On the Compound Audio Object editor, right-click on the highlighted audio object, and select Upgrade Audio Object from the context menu.
3. Click Save and close the Compound Audio Object editor.
   After this modification, the CAO in the signal flow design updated and highlighted in blue color.
4. Right-click on the highlighted compound audio object, and select Upgrade Audio Object from the context menu.
   Once the CAO is successfully upgraded, the GTT will notify you.

Upgrading the block ID will not support if it is changed from normal format to extended format in the DLL.

Audio engineers require a method for conducting A/B testing of signal flows and load balancing, as well as a simpler way to troubleshoot tuning data if errors occur.

You can achieve this by using the “Processing State” functionality, where you can change the audio object processing state.

The processing State function is only available when the device is connected.

These options are available to all audio objects except interface objects like Audio-In, Audio-Out, Control-In, and Control-Out. For the compound audio object, the selected state will be applied to all inner audio objects.

Following are the tasks carried out on the xAF side for each state:

• Normal: Normal operation with the update of necessary internal states of the audio object; normal output.
• Bypass: Normal operation with the update of necessary internal states of the audio object; input channel buffer data copied to the output channel buffers.
• Mute: Normal operation with the update of necessary internal states of the audio object; output channel buffers cleared.
• Stop: Input channel buffer data copied to the output channel buffers (no update of internal states).

The above states are only available through GTT for regular audio objects, and only Normal and Mute states are available for source objects such as Waveform generators.

Audio object which has a state other than ‘Normal’ cannot be tuned through the Native Panel.

Ramping

Linear ramping is provided with a ramp-up or ramp-down time of 50 ms. to ensure a smooth transition between states.
Ramping is not provided for any transitions involving the Bypass state, and each audio object must support it.
For the transition between Normal and Stop states, first the output is ramped down from the present state to the Mute state and then ramped up to the target state.
Every time you connect GTT to the device, audio object states from the device are read and applied to the signal flow designer. If you reboot the device, the processing states of Audio Objects will be set to ‘Normal’.

In signal flow designer you can reset all audio objects processing state to ‘Normal’ by using the ‘Reset’ button.

The undo and redo feature allows you to reverse or redo previous actions.

• Undo: The undo feature allows you to reverse the previous action by restoring the design state to a previous design state.
• Redo: The redo feature allows you to perform the action that is undone.

Undo and redo feature is not available in the tuning flow view.

Undo/Redo operation is supported for the following actions:

• Add/Remove of audio objects.
• Add/Remove of audio object connections Audio object movements.
• Audio object property changes.
• Additional parameter, additional parameter config changes Pin label, connection label changes.
• Copy/Paste of audio objects.
• Audio object processing state actions.
• Extract CAO.

The scope of Undo/redo will be within the specific instance.

In some cases, a toast message appears to help invisible items getting undone or re-done.

• Additional parameter config panel changes.
• When processing state cannot be applied.

Undo/redo action will not restore the tuning data.

This feature is limited to 1000 actions.

When a new manual action is perfromed, all existing redo records will be cleared. As a result, it will not be possible to redo any previous actions.

Before creating a signal flow, it is necessary to complete the following configurations.

• Make sure you need to add a device to the project. For more information on how to create a project and add device to the project, refer Create a New Project.
• Once you have created the signal flow, the next steps involves tuning and analyzing the signal flow. To analyze the signal flow according to your specific requirements, you need to configure the analyzer settings. The analysis can be performed using the IVP RTA window. For more details on IVP RTA settings, refer Real Time Analyzer User Guide.

If you are running a virtual device select WIN32(legacy) or WIN64 (IVP and VST3).

Not matching core types will cause issues on your device (virtual and real).

Follow the below steps to create a signal flow design:

1. On the Device View, drag and drop the Xaf Instance from the toolbox to the virtual core
   
   This action opens the Configure I/O Channels message box.
2. Enter the Input channel and Output channel value and click OK. The audio objects inside the signal flow designer are filtered based on Data Format of the core.
   
3. Select the Xaf Instance and configure the core object properties; Sample Rate and Block Length.
   • Sample Rate: This sample rate will be applied to all the audio blocks in the signal flow
   • Block Length: It is required internally by the xAF framework.
     
4. Once you configured the Xaf Instance core object properties, click Save.
5. Double-click on the Xaf Instance to open the Signal Flow Designer window.
6. On the Signal Flow Designer, go to the Toolbox section, expand Interface, and drag AudioIO audio object to the design canvas. Similarly add another AudioIO audio object to the design canvas.

   When adding an xAF instance to a device that is already online, this AudioIO can be added. Thus, this step is only necessary if these two AudioIO objects are absent.
   

7. Select one of the AudioIO audio object and set the Object Mode parameter to Audio In. Similarly, select another AudioIO audio object and set the Object Mode parameter to Audio Out.
   
8. Expand Basic and drag Gain audio object to the Signal Flow view. You can use any of the audio object, for example Gain audio object is used.
9. Select the Gain audio object and set # of channels parameter to 2.

   The number of channels determines the number of connectors that will be assigned to the AO. In GTT, you can allocate as many channels as required for your device.
   

10. Press CTL+A or hold the CTRL key, to select an individual audio object from the Signal Flow view, and click Connect Blocks to connect all the audio object.
    Or
    You can connect the pin manually by establishing a connection between each pin of the AO.
    
    Now you have an input and output object, as well as an object to tune gain, invert, and mute parameters for each channel of signal flow designer.
11. Click Save to save the signal flow design and click Go Back.
12. Click on Send Signal Flow.

    Before performing the “Send Signal Flow” operation, make sure that the IVP is properly configured.

    A pop-up message will ask you to reboot device.

13. Switch to IVP RTA tab and click Reboot.
14. Switch to Device Designer tab and click on Connect Device to connect to device.
    
15. Device synchronization dialogue box will appear, enable the desired synchronization option, and click Send.
    
    

If AmpSrv is unable to connect, close it and retry.

Now you can perform tuning on the IVP RTA.
A message “Signal flow successfully submitted” will be displayed. The Signal Flow will be sent to the virtual amplifier.
Using the Export option, you can export the signal flow design details. One .mcd file will be generated for master control data, and one .SFD file will be generated per instance per core.

The Harman Audio Library Service (HAL) service is a wrapper around the xAFVirtualAmp library. It’s been created mainly because GTT is a 64-bit application, while xAFVirtualAmp is a 32-bit library, hence it is not possible to launch both binaries in the address space of the same process. In addition, GTT also supports 64-bit xAFVirtualAmp from “R Release”.

Internally, the HAL service is implemented as a WCF service hosted in a Windows service. It communicates with GTT via named pipes.

The Harman Audio Library Service exposes the following xAF API to GTT.

• getAudioToolboxBuffer: Returns the AudioToolbox.xml file as a string. AudioToolbox.xml contains definitions of audio blocks known to a particular version of the xAFVirtualAmp library.
• getIoObjectInformation: This method accepts audio block configuration parameters and returns the IO layout of the block (# audio ins, # audio outs, # control ins and # of control outs).
• getTuningInformationBuffer: Returns a device description snippet for an audio block. Iterative invocation of that method for each audio block across all framework instances produces a device description file.

After a successful installation of GTT, the HAL service should be automatically initiated by default.

In case the service is not operational or has been deactivated for any reason, the GTT will notify you of such situations through error messages.

To activate the HAL services:

1. Open GTT project window, click on Service Monitor. This opens service monitor window.
   
2. On the Service Monitor window, click Refresh for Harman Audio Library.
   

In order to achieve complex reverb processing implementation, you can provide feedback of one audio object to another audio object, this can be achieved by adding feedback connections in signal flow. You can add one or more feedback connections in a signal flow.

On adding any audio connection, if loop detected in signal flow, following prompt will appear. On clicking “Yes”, the connection will be changed as feedback connection. On clicking “No”, the connection will be added as a normal connection.

An existing audio connection can be changed to feedback connection using context menu option “Set as Feedback Connection”.

An existing feedback connection can be changed to normal connection using context menu option “Set as Normal Connection”.

The keyboard shortcut “Ctrl+Alt+F” can be used to set a normal connection as feedback connection or vice versa. You can select one or more connections and use this keyboard shortcut.

The feedback connection will be shown as dashed yellow line as below,

You can mark any audio connection as feedback connection. But remember that, the feedback connections will be ignored/skipped during execution order calculation.

If any loop connection detected on save or if a legacy signal flow already has a loop connection, the designer will indicate this and an error with the compiler will be reported. In order to save the signal flow, you must first remove any existing loops or set the loop connections as feedback connections.

Feedback connections are supported inside CAO and on connections of CAO.

Self-loop is not allowed on an audio object.

The execution order of audio objects will not be changed on adding new feedback connections in a signal flow. But changing an existing connection to a feedback connection can affect execution order because the feedback connections will be ignored during execution order calculation.

InPlaceComputation will be disabled on audio objects with feedback loop connection. This includes audio objects which are source and target of feedback connection.

Separate stream indexes will be allocated for feedback connections. Same index will be allocated for input and output streams of feedback connection. These indexes when in use, will not be reused for other connection.

There is no restriction to add loops in control connections.

The xAF framework is designed to support a single core and a single instance running on that core as its default setting. However, it is possible to create a personalized xAFVirtualAmp version that supports multiple framework instances to be distributed over several cores.

Currently, the audio routing between cores at the device level and between instances at the core level is hardcoded. In the future, it will be possible to provide the routing configuration using GTT.

For now, the tool makes it possible to build signal flows consisting of multiple cores and framework instances, as well as to generate device descriptions for such setups. However, when creating a multi-core, multi-instance arrangement, it is necessary to have prior knowledge of the audio routing hardcoded in the xAFVirtualAmp library and adhere to its limitations.

Once the design is done, you can send a complete configuration (control configuration for a device and signal flow configurations for each framework instance) to a real or virtual device.

After completing the design, it is possible to send a complete configuration (including control configuration for a device and signal flow configurations for each framework instance) to a physical or virtual device.

To send configuration to a physical or virtual device:

1. On the Device Designer view, click on Send Signal Flow.
   

Audio Objects may require a different set of configuration properties than the default ones like # of channels, audio inputs, audio outputs, and number of elements. In such cases, it is possible to customize the configuration properties of the AO to better match the specific requirements of the device.

The LUT audio object serves as a suitable example; you need to define the number of rows and columns in the table. To facilitate this requirement, additional configuration parameters are added in both GTT and xAF.

Theoretically, an audio block can have any number of additional configuration parameters. These parameter definitions are obtained from the xAF library in conjunction with the parent block definition. The parameter definition consists of parameter order, name, and value, which are currently represented as floats. There are plans to enhance parameter definitions in the future to accommodate multiple parameter types.

When a metadata is available, the additional parameters are displayed as shown below.

On the Audio Object Property view, click on the Configure. The system will open an additional parameters window, where you can provide additional parameters. These additional parameters are of the same data type which is provided as part of parameters definition.

After making the necessary modifications, click the Apply and the system will implement the designated supplementary parameters.

Dynamic Additional Parameters

This feature is to change the size of additional parameters based on IO modifications. This feature is available for selected Audio objects which have “isAddVarUpdateRequired” flag set in their static metadata.