Acoustic system

An acoustic system, comprising:

• a loudspeaker;
• a processor configured to drive the loudspeaker with an audio signal;
• and
• a sensor configured to detect a displacement of a vibration system of the loudspeaker in an axial direction of the loudspeaker,
• wherein the loudspeaker includes a first voice coil and a second voice coil that, when viewed in a radial direction of the loudspeaker, are situated in a gap in which a magnetic flux propagates in the radial direction,
• wherein a size of a range of the first voice coil in the axial direction of the loudspeaker is greater than a size of a range of the gap in the axial direction, and a size of a range of the second voice coil in the axial direction is less than the size of the range of the first voice coil in the axial direction,
• wherein the range of the second voice coil in the axial direction falls within the range of the first voice coil in the axial direction, and
• wherein the processor functions as:
• a first driver configured to apply an audio signal amplified at a first amplification factor, which is set, to the first voice coil;
• a second driver configured to apply an audio signal amplified at a second amplification factor, which is set, to the second voice coil, and
• wherein the processor:
• sets 0 as the second amplification factor and sets a first standard amplification factor, which is a predetermined amplification factor, as the first amplification factor when a position of the second voice coil in the axial direction represented by the displacement detected by the sensor is within a non-interactive range in which the second voice coil is unable to interact with the magnetic flux propagating in the gap;
• and sets 0 as the first amplification factor and sets a second standard amplification factor, which is a predetermined amplification factor, as the second amplification factor when the position of the second voice coil is within an interactive range in which the second voice coil is able to properly interact with the magnetic flux propagating in the gap.