Loudspeakers
AssigneeGP Acoustics (UK) Limited
InventorJack Anthony Oclee-Brown
Life of this patent
Estimating the term…
Abstract
Apparatus and methods for a velocity-sensing approach to loudspeaker motional feedback comprising providing a first magnetic field to couple primarily with the voice coil to drive the voice coil, providing a second magnetic field to couple primarily with the sensing winding, and sensing the voltage induced in the second, sensing winding as it reciprocates in the second magnetic field. The second magnetic field has an orientational periodicity which is circumferential in relation to the reciprocation axis and this orientational periodicity extends over at least a part of the length of the former along the reciprocation axis.
Claims18
A method of measuring the instantaneous velocity of a loudspeaker driver reciprocating in a magnetic field, the driver having a voice coil wound coaxially around a former in a helical path and a sensing winding arranged coaxially around the former, the driver being driven so as to reciprocate along a reciprocation axis by the application of an electric signal to the voice coil, the method comprising providing a first magnetic field arranged and adapted to couple primarily with the voice coil, providing a second magnetic field arranged and adapted to couple primarily with the sensing winding, and sensing the voltage induced in the second, sensing winding as it reciprocates axially in the second magnetic field, wherein the second magnetic field has an orientational periodicity which is circumferential in relation to the reciprocation axis and which orientational periodicity extends over at least a part of the length of the former along the reciprocation axis.
A loudspeaker comprising:
- a voice coil wound coaxially around a former in a helical path which together are adapted, when an electric signal is applied to the voice coil, to reciprocate along a reciprocation axis within a gap in a magnet arrangement so as to cause an acoustic diaphragm connected to the former to reciprocate along the reciprocation axis and radiate acoustic energy, the voice coil extending a first distance along the axis and the former, and
- a sensing winding arranged coaxially around the former and extending a second distance along the reciprocation axis,
- in which the magnet arrangement is adapted and configured to generate two magnetic fields, a first magnetic field primarily for driving the voice coil to reciprocate and located axially adjacent the first distance, and a second magnetic field located axially adjacent the second distance and adapted to couple primarily with the sensing winding, and in which the sensing winding is arranged around the circumference of the former in the form of an even number of loops, the loops being separately disposed around the circumference of the former but electrically connected to form a single winding, each loop extending around a loop axis which is substantially perpendicular to the reciprocation axis.
A former for a loudspeaker, the former comprising a voice coil wound coaxially around the former in a helical path, the former and voice coil being adapted to reciprocate along a reciprocation axis within a gap in a magnet arrangement so as to cause an acoustic diaphragm connected to the former to reciprocate along the reciprocation axis and radiate acoustic energy, the former comprising a sensing winding formed on the outer and/or inner surface of the former in one or more printed circuit layers comprising a plurality of separate sensing coils disposed circumferentially about the former, each coil comprising a plurality of adjacent turns, the sensing coils being separately disposed around the circumference of the former but electrically connected to form a single winding, each sensing coil extending around a loop axis which is substantially perpendicular to the reciprocation axis.
Dependencies are inferred from the claim text.