Abstract: An apparatus for simulating the acoustic performance of an automotive vehicle, the apparatus comprising: a processor configured to select an electrical input to be provided to the amplifier in dependence on one or more driving conditions for the vehicle, the electrical input indicating a desired acoustic output for a vehicle and being selected from a plurality of prestored electrical inputs; an amplifier configured to receive the electrical input from the processor and to generate amplified electrical signals of the acoustic output from the electrical input; a transducer configured to generate acoustic vibrations from electrical signals received from the amplifier; and a structural panel configured for placement on the body of the vehicle, wherein the transducer is mounted to the panel such that acoustic vibrations generated by the transducer are emitted from the panel to an environment within or surrounding the vehicle.

Abstract: A sound bypass device configured to transmit engine-generated sound pulses from an engine to a sound outlet whilst preventing flow of gases to the sound outlet, the sound bypass device comprising: an input tube configured to conduct the engine-generated sound pulses from the engine; and a sound transmission device connected to the input tube at a first end and to the sound outlet at a second end, the sound transmission device comprising: a first volume connected to the first end, a second volume connected to the second end, and a flexible diaphragm separating the first volume from the second volume and configured to transfer variations in pressure in the first volume to the second volume; wherein the first volume has a cross-sectional area that is greater at the diaphragm than at the first end and the second volume has a cross-sectional area that is greater at the diaphragm than at the second end.