| CPC H04R 11/02 (2013.01) [H04R 2400/07 (2013.01); H04R 2400/11 (2013.01); H04R 2499/13 (2013.01)] | 12 Claims |
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1. A loudspeaker including:
a frame, a diaphragm suspended from the frame and a drive unit;
wherein the drive unit has a stationary part secured to the frame and a translatable part secured to the diaphragm;
wherein the translatable part of the drive unit includes a magnet unit which includes at least one permanent magnet, a washer and a yoke, wherein the magnet unit is configured to produce a magnetic field in an air gap between the washer and a sidewall of the yoke, wherein the at least one permanent magnet, the washer and the yoke are configured to guide magnetic flux provided by the at least one permanent magnet to the air gap;
wherein the stationary part of the drive unit includes a voice coil configured to sit in the air gap when the diaphragm is at rest;
wherein the at least one permanent magnet has a first mass, the voice coil has a second mass, and the first mass is smaller than the second mass;
wherein the loudspeaker is operable to energise the voice coil to cause the magnet unit to move along a movement axis relative to the voice coil, thereby moving the diaphragm along the movement axis to produce sound;
further including a first suspension element attached to the frame at a first landing surface on the frame and a second suspension element attached to the frame at a second landing surface on the frame, wherein the centre of gravity of the translatable part of the drive unit has a position along the movement axis that is between the first landing surface and the second landing surface;
wherein the loudspeaker is provided as a subwoofer configured to produce sound with frequencies in a bass frequency range.
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