A seat assembly including: a seat for seating a user; a loudspeaker (101, 201, 301, 401, 501) for producing sound at bass frequencies, the loudspeaker including: a diaphragm (110, 210, 510) having a first radiating surface (112, 212) and a second radiating surface, wherein the first radiating surface (112, 212) and the second radiating surface are located on opposite faces of the diaphragm (110, 210, 510); a drive unit (220, 520) configured to move the diaphragm (110, 210, 510) along a movement axis at bass frequencies such that the first and second radiating surfaces produce sound at bass frequencies, wherein the sound produced by the first radiating surface (112, 212) is in antiphase with sound produced by the second radiating surface; and a drive unit frame (130, 230, 430, 530), wherein the diaphragm (110, 210, 510) is suspended from the drive unit frame (130, 230, 430, 530) via at least one drive unit suspension (232, 233); the seat assembly further including a mounting frame (140, 240, 440, 540), wherein the drive unit frame (130, 230, 430, 530) is suspended from the mounting frame (140, 240, 440, 540) via a mounting frame suspension system that includes at least one mounting frame suspension; the seat assembly being characterised by further including an adjustment mechanism configured to adjust the mounting frame suspension system so as to change the extent to which vibrations generated by the loudspeaker (101, 201, 301, 401, 501) reach the mounting frame via the mounting frame suspension system when the loudspeaker (101, 201, 301, 401, 501) is in use; and a control interface configured to control the adjustment mechanism so as to adjust the mounting frame suspension system based on user input at the control interface. a seat for seating a user; a loudspeaker (101, 201, 301, 401, 501) for producing sound at bass frequencies, the loudspeaker including: a diaphragm (110, 210, 510) having a first radiating surface (112, 212) and a second radiating surface, wherein the first radiating surface (112, 212) and the second radiating surface are located on opposite faces of the diaphragm (110, 210, 510); a drive unit (220, 520) configured to move the diaphragm (110, 210, 510) along a movement axis at bass frequencies such that the first and second radiating surfaces produce sound at bass frequencies, wherein the sound produced by the first radiating surface (112, 212) is in antiphase with sound produced by the second radiating surface; and a drive unit frame (130, 230, 430, 530), wherein the diaphragm (110, 210, 510) is suspended from the drive unit frame (130, 230, 430, 530) via at least one drive unit suspension (232, 233); the seat assembly further including a diaphragm (110, 210, 510) having a first radiating surface (112, 212) and a second radiating surface, wherein the first radiating surface (112, 212) and the second radiating surface are located on opposite faces of the diaphragm (110, 210, 510); a drive unit (220, 520) configured to move the diaphragm (110, 210, 510) along a movement axis at bass frequencies such that the first and second radiating surfaces produce sound at bass frequencies, wherein the sound produced by the first radiating surface (112, 212) is in antiphase with sound produced by the second radiating surface; and a drive unit frame (130, 230, 430, 530), wherein the diaphragm (110, 210, 510) is suspended from the drive unit frame (130, 230, 430, 530) via at least one drive unit suspension (232, 233); the seat assembly further including a mounting frame (140, 240, 440, 540), wherein the drive unit frame (130, 230, 430, 530) is suspended from the mounting frame (140, 240, 440, 540) via a mounting frame suspension system that includes at least one mounting frame suspension; the seat assembly being characterised by further including an adjustment mechanism configured to adjust the mounting frame suspension system so as to change the extent to which vibrations generated by the loudspeaker (101, 201, 301, 401, 501) reach the mounting frame via the mounting frame suspension system when the loudspeaker (101, 201, 301, 401, 501) is in use; and a control interface configured to control the adjustment mechanism so as to adjust the mounting frame suspension system based on user input at the control interface.