A common issue in car audio tuning is the localization of bass notes. When subwoofers fire exclusively from the floor or rear quarter panels, the human ear can often detect where the low-end originate, fracturing the cabin sound staging. Rolls-Royce overcomes this psychoacoustic limitation by utilizing exciter speakers concealed inside the roof headliner.
Exciter speakers do not feature conventional paper cones or rubber surrounds. Instead, compact electromagnetic coils adhere directly to the structural headliner backing, transforming the interior trim into a sound-radiating surface.
In the Cullinan Series II, these roof exciters play two acoustic roles:
- They generate precise high- and mid-frequency spatial imaging for the vehicle's simulated concert settings.
- They produce critical upper-bass harmonic overtones that match the primary output of the chassis-mounted low-frequency transducers.
Because the human brain tracks the direction of sound using upper harmonics, the exciters lift the acoustic soundstage to eye level. The deep, physical fundamental notes resonate outward from the aluminum sill cavities, while the melodic bass details linger at ear height. The listening experience mirrors that of a purpose-built mastering studio rather than a moving vehicle.
