Leading the Engineering team at Meridian and working with McLaren Automotive cross-functional teams, two Meridian Sound Systems were designed and developed for McLaren Automotive vehicles.
The cross-functional teams collaborated on the design of loudspeaker drive units and their location within the cabin, the equalisation of the sound balance, HMI design/functionality and developing communication assests for promotional activities.
Meridian’s proprietary Trifield processing was configured to provide the optimum performance for automotive applications and is featured on the optional Meridian Surround Sound System to provide authentic rendering of a musical performance for all occupants in the vehicle.
DSP Amplifier
The amplifier unit contains the system’s DSP (Digital Signal Processing) capability in the form of a 200MHz dual core processor delivering 400 MIPS (million instructions per second).
There are standard, passive controls for bass, treble, balance and rear gain. The active controls tap into the CAN (controller area network) bus to access dynamic data for speed, revs, selected gear and powertrain mode.
The Dynamic Range Control (DRC) function allows the system to compensate automatically for variations in factors such as ambient noise to maintain a consistent level of perceived audio performance irrespective of driving activity.
The Automatic Volume Control (AVC) function adjusts the volume of the sound system to compensate for estimated engine, road (tyre) and wind noise. There are three settings for AVC: Off, Min and Max. ‘Off’ disables the AVC function and the volume remains constant at the user-selected level regardless of vehicle speed. ‘Min’ is the lowest setting of the AVC system: the volume adapts gently to vehicle speed and other parameters. This mode has been calibrated for smooth road surfaces. ‘Max’ is the highest setting. Here, the volume adapts more aggressively to changes in vehicle speed and other parameters. This mode has been calibrated for rougher road surfaces.
The AVC also raises the volume when the engine is started and compensates for a lowered window by raising the volume on that side of the vehicle. The volume correction for the window function is also road-speed dependent.
In Normal and Winter powertrain modes, the AVC operates with road speed and rpm. In Sport and Track powertrain modes, the AVC also uses throttle position to add compensation for the increased engine noise generated by the ISG.
The Automatic Tone Control (ATC) boosts the bass to compensate for the masking effect of the low frequency noise of the engine. Both bass and treble are automatically adjusted with road speed to compensate for road and wind noise. More aggressive correction is applied when the powertrain mode is set to Sport or Track.
Loudspeaker Assemblies
The two primary loudspeaker enclosure assemblies are the same in both systems, and consist of a 165mm (6.5in) low frequency drive unit (illustrated above left) and an 85mm (3.5in) full range driver (illustrated above right: not to scale) installed in sealed enclosures, which are door-mounted. The low frequency drive units carry the bass signals for the entire system. These two units comprise the loudspeaker assemblies for the stereo (2.2) system.
In the case of the surround (5.2) system, these units are augmented by three additional 85mm full-range drivers (illustrated above), one mounted in the fascia and two behind the seats, left and right.
In all configurations, whatever the source material, the DSP-based crossover and bass management system ensures maximum performance and sonic accuracy are delivered at all times. The drivers are individually digitally equalised according to their location and enclosure characteristics, to create a completely integrated replay system in which all the loudspeakers work together to fill the in-car environment with pure, natural, digital sound, exactly tailored for the unique acoustic environment of the MP4-12C.