What is a Device?
A device is defined as a microphone array with one or multiple microphones. The microphones are placed on a 3D geometry of e.g. a wearable device, smartspeaker, conference device, etc. It is desirable to not include the 3D geometry of the device in the room simulation, but instead render it in, in post processing (the Treble way) for several reasons. Fine mesh details often found on imported 3D geometries negatively affects computational run time. If you want to turn the device or add more microphones to it, it is much faster to render in the device in post processing instead of having to run the room simulation again.
In Treble, we refer to Device Related Transfer Functions (DRTF) as devices where we can transform the response at a spatial receiver to the response as if a particular device, described by a DRTF, was located at the location of the spatial receiver. This is done by isolating the effect that a device has on the wavefield and adding it in, in post-processing.
On a high level, this is done by projecting the effect of the device on to a spherical harmonics basis and then projecting the response of the spatial receiver to the same basis. The two effects can then be combined in post, including any potential rotation of the device. In our results section we cover how a device can be imported in to a simulation in post-processing.
The benefits of this approach are:
- Ability to switch out devices without running a new simulation.
- Ability to rotate devices at will afterwards.
- Enabling the inclusion of such devices in GA and hybrid simulations as well as the wave-based ones.
- The option to rapidly test device design prototypes and mic array configurations.
- Extending a dataset by augmenting it with multiple "listeners"
We provide then ability to create such devices to a varying degree of accuracy, using different ambisoncis orders. We recommend reading the guide on picking an appropriate ambisonics order for your device.
The created device can be imported in to simulation where there is a spatial receiver. This covered more in depth in our results section.