Passenger vehicle
A vehicle component for mounting in a passenger compartment of a vehicle, the component comprising a loudspeaker having an acoustic radiator capable of supporting bending wave vibration and an electromechanical force transducer mounted to the acoustic radiator to excite bending waves in the acoustic radiator to produce an acoustic output, characterized in that the transducer has an intended operative frequency range and comprises a resonant element having a frequency distribution of modes in the operative frequency range and a coupler on the resonant element for mounting the transducer to the acoustic radiator.
1. A vehicle component for mounting in a passenger compartment of a vehicle, the component comprising:
a loudspeaker having at least one acoustic radiator capable of supporting bending wave vibration; and
an electromechanical force transducer mounted to the acoustic radiator to excite bending waves in the acoustic radiator to produce an acoustic output, wherein the transducer has an intended operative frequency range and comprises:
an active resonant element having a frequency distribution of modes in the operative frequency range, wherein parameters of the resonant element are selected to enhance the distribution of modes in the resonant element in the operative frequency range, and wherein the distribution of modes in the resonant element has a density of modes which is sufficient for the resonant element to provide an effective mean average force which is substantially constant with frequency; and
a coupler for mounting the transducer to the acoustic radiator.
2. A vehicle component according to claim 1 , wherein the modes are distributed substantially evenly over the intended operative frequency range.
3. A vehicle component according to claim 1 , wherein the resonant element is modal along two substantially normal axes, each axis having an associated fundamental frequency, and wherein the ratio of the two associated fundamental frequencies is adjusted for best modal distribution.
4. A vehicle component according to claim 3 , wherein the ratio of the two fundamental frequencies is about 9:7.
5. A vehicle component according to claim 1 , wherein the transducer comprises a plurality of resonant elements each having a distribution of modes, the modes of the resonant elements being arranged to interleave in the operative frequency range whereby the distribution of modes in the transducer is enhanced.
6. A vehicle component according to claim 1 , wherein the resonant element is plate-like.
7. A vehicle component according to claim 1 , wherein the shape of the resonant element is selected from the group consisting of beam-like, trapezoidal, hyperelliptical, generally disc shaped or rectangular.
8. A vehicle component according to claim 7 , wherein the resonant element is plate-like.
9. A vehicle component according to claim 1 , further comprising:
grooves adapted to form a generally rectangular acoustically active area.
10. A vehicle component according to claim 9 , wherein the generally rectangular acoustically active area is stiffened with a lightweight cellular core to form a panel-form acoustic radiator.
11. A vehicle component according to claim 9 , wherein parameters of the resonant element are selected to enhance the distribution of modes in the resonant element in the operative frequency range.
12. A vehicle component according to claim 11 , wherein the distribution of modes in the resonant element has a density of modes which is sufficient for the resonant element to provide an effective mean average force which is substantially constant with frequency.
13. A vehicle component according to claim 11 , wherein the modes are distributed substantially evenly over the intended operative frequency range.
14. A vehicle component according to claim 1 , wherein the component is selected from one of an internal trim, an interior door pillar, an interior vehicle centre console, a parcel shelf, a sun visor, a rear view mirror, a headrest, and a seat back.
15. A vehicle component according to claim 1 , wherein the component is a sun visor, wherein the loudspeaker comprises two acoustic radiators, wherein the transducer is sandwiched between the two radiators, and wherein the transducer is mounted to drive both radiators simultaneously.
16. A vehicle component according to claim 15 , wherein parameters of the resonant element are selected to enhance the distribution of modes in the resonant element in the operative frequency range.
17. A vehicle component according to claim 16 , wherein the distribution of modes in the resonant element has a density of modes which is sufficient for the resonant element to provide an effective mean average force which is substantially constant with frequency.
18. A vehicle component according to claim 16 , wherein the modes are distributed substantially evenly over the intended operative frequency range.
19. A vehicle comprising a passenger compartment and a vehicle component mounted in the passenger compartment, the component comprising:
a loudspeaker having an acoustic radiator capable of supporting bending wave vibration; and
an electromechanical force transducer mounted to the acoustic radiator to excite bending waves in the acoustic radiator to produce an acoustic output, wherein the transducer has an intended operative frequency range and comprises:
an active resonant element having a frequency distribution of modes in the operative frequency range, wherein parameters of the resonant element are selected to enhance the distribution of modes in the resonant element in the operative frequency range, and wherein the distribution of modes in the resonant element has a density of modes which is sufficient for the resonant element to provide an effective mean average force which is substantially constant with frequency; and
a coupler for mounting the transducer to the acoustic radiator.