A centrefill driver is usually employed as part of a surround sound system in the middle of the dashbaord to reproduce centre-stage content. In terms of integration, the upfiring driver reflects sound off the windscreen and radiates sound towards the occupants. In the model, this scenario has been simplified but represents a typical arrangement.
Centrefill Driver in Car Model
The excitation pulse (Hann function) represents the displacement function of the centrefill piston. The time-domain response to this is captured in the FE model of the car cabin, which is the same model as was used in the frequency domain analysis
Radiation from Pulsed Driver - display plane from centrefill loudspeaker location to listener (driver)
|Front Driver - Left Ear||Front Driver - Right Ear|
Interesting features to note are the separation of the wavefront due to the reflection from the window and the secondary arrival around 2-3 ms following the first pulse. Regarding the wavefront separation, there may be an opportunity to optimise the geometrtical relationship of the driver to the surrounding reflective elements to ensure maximum amplitude at the listener ears rather than the surrounding space.
|Sideways Radiation - Reflection from Pillars||Delayed Radiation from Colliding Reflections|
The secondary arrival to the listener may be a potentially distracting artefact to some occupants and it may be desirable to utilise a more directional forward-firing driver for this purpose, perhaps a small horizontal array to minimise radiation towards the side pillars.