Smaart Loopback: The New Generator

Smaart Loopback: The New Generator

Since upgrading to v9.3, you may have noticed a new checkbox option in the I-O Config menu: Smaart Loopback. You may have also noticed that the Generator device no longer is listed in your input devices tab of I-O config.

In previous versions, generator loopback was treated as its own audio device, which caused multiple issues when trying to reference internally. In the previous workflow, you would turn on the "Multi-Device Transfer Function" option in advanced preferences and use the generator device as a separate input. 

In Smaart v9.3 we introduced Smaart Loopback, which allows any enabled output channel to appear as an input under Smaart Loopback in the associated device's channel dropdown list during measurement engine creation. This allows any device to act as the generator, creating a stable relationship in time between Smaart's generator loopback and your input device.

Any device can act as the generator; there is no dedicated generator device as all devices are capable of being the generator. 

To turn on Smaart Loopback, enable it from the Output tab of the IO Config window. Once the box is checked, all selected output channels will become available in the Channel Selection drop-down menus for spectrum and transfer function engines.

If you've recently updated Smaart and still see the Generator as its own device in the I-O Menu, please navigate to Config > Manage Configurations > Restore Defaults to remove the old generator device.

To Use Smaart Loopback:

    1. In Output Device Configuration, enable Smaart Loopback and select your intended output device(s) and channel(s).

    2. You will be met with a quick warning message by default. The Transfer Function measurement engines referenced to Smaart Loopback are not delay-compensated and the resultant delay times will be the sum of the measurement's propagation delay and the delay of any audio buffers in use in the Smaart Loopback channel. While this warning may have a jarring appearance, it is simply there to notify you of this additional latency and should not effect the outcome of your measurement.

Depending on what you're measuring with Smaart Loopback, this additional latency is negligible, but it is still important to note. The same would be true if you were using the old generator device for a multi-device transfer function. This latency should not affect your tuning decisions, but it can seem alarming without a heads-up.

    2.5. If you are using Wave drivers on Windows, your interface's inputs are treated as a different device from its outputs. As such, you'll first need to enable "Multi-Device TF" in the Advanced Settings menu before you'll be able to use Smaart loopback with Wave drivers. This menu can be accessed by either navigating to Options > Preferences > Advanced or by using the [Alt/Option] + [J] hotkey.

That being said, the delay added via the Multi-Device TF setting will compound with the additional delay added by Smaart Loopback, which may not be ideal. To avoid this, we recommend choosing ASIO drivers over Wave, if possible.

    3. In your measurement engine configuration channel dropdown, select the output channel under the Smaart Loopback header. All outputs you selected for use will show up as inputs under the corresponding device. From there on, you can set up your measurement channels as usual and you're good to go!