Abstract: A loudspeaker with a non-uniform surround, a membrane and a stiffening element preventing the surround from flexing the membrane during operation. A non-uniform surround does not have the same cross section, along the radius of the speaker if circular, all around the perimeter of the membrane as some portions will be upwardly directed and other portions downwardly directed.

Abstract: The present invention relates to a motor for an electrodynamic loudspeaker, comprising a magnetic circuit assembly arranged about a motor axis. The magnetic circuit assembly comprises: an outer magnet, a magnetically permeable top plate, a magnetically permeable bottom plate, a center pole piece and an air gap for receipt of a voice coil. The air gap is formed by an inner axially extending wall of the magnetically permeable top plate facing an axially extending peripheral wall section of the center pole piece to define a width, a bottom, a top and height of the air gap. The magnetic circuit assembly additionally comprises outwardly projecting magnetically permeable member arranged above the top of the air gap. The center pole piece comprises a magnetic member extending axially from at least the bottom of the air gap to a magnetically permeable bottom member or to the magnetically permeable bottom plate.

Abstract: --A motor for an electrodynamic loudspeaker and an electrodynamic loudspeaker including the motor. The motor includes a magnetic circuit assembly arranged about a motor axis. The motor includes: a magnetically permeable top plate, a magnetically permeable bottom plate, a magnetically permeable member disposed between, and magnetically coupled to, the magnetically permeable top and bottom plates, a center pole piece and an air gap for receipt of a voice coil. The motor also includes an outwardly projecting magnetically permeable member, or hat, arranged above a top of the air gap. The center pole piece includes a permanent magnet, such as a Neodymium magnet or a Ferrite magnet, extending axially from at least the bottom of the air gap to a magnetically permeable bottom member or to the magnetically permeable bottom plate.

Abstract: An amplifier, such as a Class D amplifier, having one or more feedback loops comprising a path from the input to the primary amplifier input, where the paths comprise a low pass filter and a compensator which is disabled when the primary amplifier clips.

Abstract: A loudspeaker with a non-uniform surround, a membrane and a stiffening element preventing the surround from flexing the membrane during operation. A non-uniform surround does not have the same cross section, along the radius of the speaker if circular, all around the perimeter of the membrane as some portions will be upwardly directed and other portions downwardly directed.

Abstract: A motor for an electrodynamic loudspeaker. The motor includes a magnetic circuit assembly arranged about a motor axis. The assembly includes: an outer magnet, a magnetically permeable top plate, a magnetically permeable bottom plate, a center pole piece and an air gap for receipt of a voice coil. The air gap is formed by an inner wall of the magnetically permeable top plate facing an axially extending peripheral wall section of the center pole piece to define the air gap. The magnetic circuit assembly also includes an outwardly projecting magnetically permeable member arranged above the air gap. The center pole piece has a magnetic member extending axially from the bottom of the air gap to a magnetically permeable bottom member or to the bottom plate. The magnetic member exhibits a relative AC magnetic permeability smaller than 10, which corresponds to the relative AC magnetic permeability of free air.

Abstract: The present invention discloses a loudspeaker driver comprising a magnet system having at least one gap where in each gap a voice coil assembly is arranged for movement in the gap, wherein either two distinct coils are arranged on the voice coil assembly, one above the other, and the magnet system comprises two pole pieces, one above the other, creating a pair of magnetized areas between said pole pieces and a yoke, such that a magnetic flux field is created between each pole piece and the yoke.

Abstract: A Class D amplifier having an integrating primary amplifier with an internal feedback, the amplifier further comprising a feedback loop with a filter of at least second order.

Abstract: An amplifier comprising a gain stage with a feedback network comprising two ports between which at least three capacitors are connected in series and between each pair of capacitors a resistor is connected to a predetermined voltage. The gain stage is provided in a feedback loop over a primary amplifier.

Abstract: The present invention discloses a loudspeaker driver comprising a magnet system having at least one gap where in each gap a voice coil assembly is arranged for movement in the gap, wherein either two distinct coils are arranged on the voice coil assembly, one above the other, and the magnet system comprises two pole pieces, one above the other, creating a pair of magnetized areas between said pole pieces and a yoke, such that a magnetic flux field is created between each pole piece and the yoke.

Abstract: An amplifier, such as a Class D amplifier, having one or more feedback loops comprising a path from the input to the primary amplifier input, where the paths comprise a low pass filter and a compensator which is disabled when the primary amplifier clips.

Abstract: A Class D amplifier having an integrating primary amplifier with an internal feedback, the amplifier further comprising a feedback loop with a filter of at least second order.

Abstract: An amplifier comprising a gain stage with a feedback network comprising two ports between which at least three capacitors are connected in series and between each pair of capacitors a resistor is connected to a predetermined voltage. The gain stage is provided in a feedback loop over a primary amplifier.

Abstract: The present invention relates in one aspect to a method of controlling or limiting diaphragm excursion of a loudspeaker. The method comprising steps of receiving a first audio signal and deriving an excursion signal representing diaphragm excursion of the electrodynamic loudspeaker from the first audio signal. The method additionally comprises deriving an excursion envelope from the excursion signal and applying a second audio signal, derived from the first audio signal, to an input of an adjustable low-frequency suppressor. The second audio signal is filtered by the adjustable low-frequency suppressor to selectively attenuate low-frequency components based on the excursion envelope to produce a processed audio signal with reduced low-frequency content.

Abstract: The present invention relates in one aspect to a method of controlling or limiting diaphragm excursion of a loudspeaker. The method comprising steps of receiving a first audio signal and deriving an excursion signal representing diaphragm excursion of the electrodynamic loudspeaker from the first audio signal. The method additionally comprises deriving an excursion envelope from the excursion signal and applying a second audio signal, derived from the first audio signal, to an input of an adjustable low-frequency suppressor. The second audio signal is filtered by the adjustable low-frequency suppressor to selectively attenuate low-frequency components based on the excursion envelope to produce a processed audio signal with reduced low-frequency content.

Abstract: A pulse width-modulated noise shaper (410) is described, which employs feedback from the power stage (260). Formation of the pulse width-modulated signal is done by applying a digital noise shaper (410) which uses feedback from the output of the power stage. Thus, any errors created by the power stage (260) are automatically corrected.

Abstract: A switching power amplifier of class D has switching means for generating a block wave signal by alternately switching the block wave signal between supply voltages. A filter (24,25) generates a power output signal (22) corresponding to an input signal to be amplified, which is coupled to a linear input (19) that is free of hysteresis. A control circuit (27,28,29) provides feedback between the output power signal and the linear input for controlling both the gain in the operational frequency range and also said alternately switching of the switching means. Hence the amplifier oscillates controlled via the same feedback loop that also controls the operational behavior of the amplifier, resulting in low output impedance and low distortion.