BMW E85 Manual page 55

E85 Information/Communication
Operating principle
High sound pressure is required for achieving a rich bass. The
Carver woofers (low-range speakers) produce this sound
pressure with their small diameter by increasing the
displacement of the diaphragm.
The sound pressure is produced by movement in the volume of
air.
The volume of air moved is derived from the diaphragm area
multiplied by the displacement.
To date to achieve this, the largest possible diaphragm area
(diameter of the speaker) was used in conjunction with relatively
low displacement (approx. 3-10 mm). A matching resonance
volume is additionally required.
In vehicle construction applications, this technology leads to a
conflict between vehicle design and vehicle equipment: Due to
the design and comprehensive level of equipment, there is little
package space available for large bass speakers.
Carver technology represents a new approach in solving this
problem. Thanks to Carver technology, a high sound pressure is
produced with a small speaker diameter by increasing the
diaphragm displacement (approx. 30 mm).
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