Inertial exciters, drive units and loudspeakers

An inertial exciter for use with an acoustic radiator, the inertial exciter comprising:

• a magnet assembly including a magnet unit configured to provide a magnetic field in an air gap, wherein the air gap extends around a movement axis of the inertial exciter;
• a coil assembly including:
• an attachment portion configured to provide an attachment between the coil assembly and the acoustic radiator;
• a voice coil;
• a voice coil former which extends from the attachment portion into the air gap, wherein the voice coil is mounted to the voice coil former so that the voice coil sits in the air gap when the inertial exciter is at rest;
• a tubular member, which is positioned radially outwardly of the voice coil former with respect to the movement axis, and which overlaps the voice coil former along at least a portion of the movement axis;
• a first suspension attached to the tubular member and a part of the magnet assembly, wherein the part of the magnet assembly attached to the first suspension is positioned radially outwardly of the tubular member;
• and
• a second suspension, separated from the first suspension in a direction extending parallel to the movement axis, wherein the second suspension is either:
• attached to the tubular member and the part of the magnet assembly positioned radially outwardly of the tubular member, or is attached to the voice coil former and a part of the magnet assembly positioned radially inwardly of the voice coil former;
• wherein the inertial exciter is configured so that, when the coil assembly is attached to the acoustic radiator via the attachment portion, the magnet assembly is suspended from the acoustic radiator via the coil assembly by the first and second suspensions.