A seat assembly including: a seat; and a loudspeaker unit, wherein the loudspeaker unit is for producing sound at bass frequencies, wherein the loudspeaker unit is mounted within a headrest of the seat and wherein the loudspeaker unit includes: a diaphragm having a first radiating surface and a second radiating surface, wherein the first radiating and second radiating surfaces are located on opposite faces of the diaphragm, and wherein the loudspeaker unit is configured to allow sound produced by the first and second radiating surfaces to propagate out from the loudspeaker unit; a drive unit configured to move the diaphragm based on an electrical signal; a frame from which the diaphragm is suspended via one or more suspension elements; drive circuitry configured to provide the drive unit with an electrical signal derived from an audio source; a first sound guide configured to guide sound produced by the first radiating surface to two first outlets (232b, 232b') and a second sound guide configured to guide sound produced by the second radiating surface to two second outlets (234b, 234b') such that the sound propagates out of the loudspeaker unit from the two first outlets and the two second outlets, each first outlet being remotely located with respect to the other first outlet of the two first outlets, and configured to be located close to a respective ear of a user, each second outlet being remotely located with respect to the other second outlet of the two second outlets and each first and second outlet being remotely located with respect to said first and second radiating surfaces; wherein the loudspeaker unit is configured so that, at the locations at which sound propagates out from the loudspeaker, and in the operational bandwidth of the loudspeaker unit, the sound produced by the first radiating surface is substantially out of phase with the sound produced by the second radiating surface. a seat; and a loudspeaker unit, wherein the loudspeaker unit is for producing sound at bass frequencies, wherein the loudspeaker unit is mounted within a headrest of the seat and wherein a diaphragm having a first radiating surface and a second radiating surface, wherein the first radiating and second radiating surfaces are located on opposite faces of the diaphragm, and wherein the loudspeaker unit is configured to allow sound produced by the first and second radiating surfaces to propagate out from the loudspeaker unit; a drive unit configured to move the diaphragm based on an electrical signal; a frame from which the diaphragm is suspended via one or more suspension elements; drive circuitry configured to provide the drive unit with an electrical signal derived from an audio source; a first sound guide configured to guide sound produced by the first radiating surface to two first outlets (232b, 232b') and a second sound guide configured to guide sound produced by the second radiating surface to two second outlets (234b, 234b') such that the sound propagates out of the loudspeaker unit from the two first outlets and the two second outlets, each first outlet being remotely located with respect to the other first outlet of the two first outlets, and configured to be located close to a respective ear of a user, each second outlet being remotely located with respect to the other second outlet of the two second outlets and each first and second outlet being remotely located with respect to said first and second radiating surfaces; wherein the loudspeaker unit is configured so that, at the locations at which sound propagates out from the loudspeaker, and in the operational bandwidth of the loudspeaker unit, the sound produced by the first radiating surface is substantially out of phase with the sound produced by the second radiating surface.