Abstract: An acoustic insert for lining a loudspeaker reflex port, the insert comprising an elongate hollow tube formed of a flexible material, having an outer wall sized and configured to seat within the port and an inner wall extending in the elongate direction, the inner wall having a circumference which varies along the length of the insert, When inserted in a port, the insert alters the port resonance so as to vary the acoustic perfoi mance of the loudspeaker.

Abstract: An acoustic insert for lining a loudspeaker reflex port, the insert comprising an elongate hollow tube formed of a flexible material, having an outer wall sized and configured to seat within the port and an inner wall extending in the elongate direction, the inner wall having a circumference which varies along the length of the insert, When inserted in a port, the insert alters the port resonance so as to vary the acoustic performance of the loudspeaker.

Abstract: A loudspeaker comprising an acoustically radiating diaphragm comprising a generally frustoconical membrane having a narrow neck end and a wide mouth end, stiffening formations for stiffening the radiating membrane and an interface region by which the diaphragm is adapted to be driven; and a transducer comprising a voice coil mounted to drive the diaphragm via its interface region; wherein the interface region is located at the node of the first mode of vibration of the diaphragm.

Abstract: A loudspeaker comprising an acoustically radiating diaphragm comprising a generally frustoconical membrane having a narrow neck end and a wide mouth end, stiffening formations for stiffening the radiating membrane and an interface region by which the diaphragm is adapted to be driven; and a transducer comprising a voice coil mounted to drive the diaphragm via its interface region; wherein the interface region is located at the node of the first mode of vibration of the diaphragm.

Abstract: A phase plug comprises a body having an input side for receiving acoustic waves and an output side for transmitting acoustic waves, the body including a plurality of channels extending from the input side to the output side for propagating acoustic waves through the body. The input side comprises an input surface which includes a plurality of openings constituting entrances for the channels, the input surface being substantially part of a sphere or an ellipsoid in shape. The areas of the openings vary with radial position on the input surface, the radial position being measured in a direction extending perpendicularly from a central axis extending through the input surface. The variation in the areas is a function of the cosine of an angle subtended at the centre of the sphere or a focus of the ellipsoid between the central axis and the radial position.

Abstract: A phase plug comprises a body having an input side for receiving acoustic waves and an output side for transmitting acoustic waves, the body including a plurality of channels extending from the input side to the output side for propagating acoustic waves through the body. The input side comprises an input surface which includes a plurality of openings constituting entrances for the channels, the input surface being substantially part of a sphere or an ellipsoid in shape. The areas of the openings vary with radial position on the input surface, the radial position being measured in a direction extending perpendicularly from a central axis extending through the input surface. The variation in the areas is a function of the cosine of an angle subtended at the centre of the sphere or a focus of the ellipsoid between the central axis and the radial position.