Abstract: An acoustic filter suitable for an electro-acoustic transducer includes a relatively high frequency driver and a relatively low frequency driver situated on a common axis. The acoustic filter includes a baffle body having an outer side and an inner side, such that the outer side serves as a baffle for the high frequency driver. The inner side forms a first wall of a Helmholtz resonator including a chamber and a vent duct communicating with the chamber.

Abstract: A loudspeaker system for a vehicle may include a vehicle partition panel that separates an interior space and an exterior space; a loudspeaker device comprising a frame, a diaphragm elastically supported at the frame, and a driving device that is configured to provide driving power for operating the diaphragm; and an air chamber disposed between the diaphragm and the vehicle partition panel. The frame delimits a chamber side opening of the air chamber facing the vehicle partition panel, where the vehicle partition panel comprises a vehicle partition panel opening. The vehicle partition panel opening has an extension which is smaller than the diameter of the diaphragm and smaller than an extension of the chamber side opening. The loudspeaker device is fixed to the vehicle partition panel such that the chamber side opening and the vehicle partition panel opening overlap in an overlapping area and the chamber side opening adjoins the vehicle partition panel opening.

Abstract: A loudspeaker assembly is disclosed for use in a loudspeaker system having infinite baffle topology. The assembly comprises a driver including a cone and a basket and at least one Helmholtz resonator including a chamber and a vent duct communicating with the chamber and adapted to pass through the infinite baffle. The chamber is dimensioned to provide a tuned frequency well above an operating band associated with the driver. The cross sectional area and length of the vent duct may be set to provide control over duct air noise and low frequency extension. A method of tuning a loudspeaker assembly for use in a loudspeaker system having infinite baffle topology is also disclosed.