Abstract: According to an example aspect of the present invention, there is provided an audio amplifier for use with a limited power source, the audio amplifier having: a power input terminal, a signal input terminal, a first DC to DC converter having an input connected to the power input terminal, an electrical energy storage device connected to an output of the first DC to DC converter, a second DC to DC converter having an input connected to the electrical energy storage device, an amplifier conductively connected to the output of the second DC to DC converter so as to be powered by the output of the second DC to DC converter, the amplifier also being conductively connected to the signal input terminal so as to receive a signal for amplification, and an output of the amplifier configured to be connected to a transducer such that the transducer may be driven by the amplifier.

Abstract: According to an example aspect of the present invention, there is provided an audio amplifier for use with a limited power source, the audio amplifier having: a power input terminal, a signal input terminal, a first DC to DC converter having an input connected to the power input terminal, an electrical energy storage device connected to an output of the first DC to DC converter, a second DC to DC converter having an input connected to the electrical energy storage device, an amplifier conductively connected to the output of the second DC to DC converter so as to be powered by the output of the second DC to DC converter, the amplifier also being conductively connected to the signal input terminal so as to receive a signal for amplification, and an output of the amplifier configured to be connected to a transducer such that the transducer may be driven by the amplifier.

Abstract: The present invention relates to a loudspeaker including an enclosure having front portion, side portions and back portion defining an inner volume, the front portion is formed as a waveguide surface and includes at least one driver in the center of the waveguide surface and is capable to radiate the main acoustic power of the loudspeaker to ambient volume in direction of first acoustic axis, and an additional driver attached to the enclosure. In accordance with the invention the additional driver is attached inside the enclosure such that a sub volume is formed inside the inner volume, the sub volume limited by the driver, spacers between the driver and the front portion, and the front portion of the enclosure, and at least one port is adapted to open from the sub volume to ambient volume either to side portion or back portion of the enclosure and at least one resonator acoustically connected to the sub volume, the resonator being tuned to at least one of unwanted resonances of the sub volume.

Abstract: According to an example aspect of the present invention, there is provided a method for calibrating a headphone including an amplifier with a memory and signal processing properties, the method comprising steps for determining a desired sound attributes for the headphone, and setting signal processing parameters in the amplifier in order to obtain the desired sound attributes either by measurement or based on the received input information from a user of the headphones.

Abstract: According to an example aspect of the present invention, there is provided a method for forming a binaural filter for a stereo headphone in order to preserve the sound quality of the headphone, whereby the sum of the direct and crosstalk paths from loudspeakers to each ear have flat magnitude responses.

Abstract: The present invention relates to a loudspeaker including an enclosure having front portion, side portions and back portion defining an inner volume, the front portion is formed as a waveguide surface and includes at least one driver in the center of the waveguide surface and is capable to radiate the main acoustic power of the loudspeaker to ambient volume in direction of first acoustic axis, and an additional driver attached to the enclosure. In accordance with the invention the additional driver is attached inside the enclosure such that a sub volume is formed inside the inner volume, the sub volume limited by the driver, spacers between the driver and the front portion, and the front portion of the enclosure, and at least one port is adapted to open from the sub volume to ambient volume either to side portion or back portion of the enclosure and at least one resonator acoustically connected to the sub volume, the resonator being tuned to at least one of unwanted resonances of the sub volume.

Abstract: According to an example aspect of the present invention, there is provided a Method for regularizing the inversion of a stereo headphone transfer function for headphone equalization, characterized by using the equation for the equalization: H S ? ? 1 - 1 ? ( ? ) = H * ? ( ? ) ? H ? ( ? ) ? 2 + ? ^ ? ( ? ) ? D ? ( ? ) = H * ? ( ? ) ? H ? ( ? ) ? 2 + [ ? ? ( ? ) + ? 2 ? ( ? ) ] ? D ? ( ? ) . in which equation HSI?1(?) is sigma inversion H*(?) is complex conjugate of a response D(?) is a delay filter introduced to produce a causal inverse HRI?1(?) H*(?) a response ?(?) is headphone reproduction bandwidth, ?(?) an estimation of the regularization needed inside that bandwidth.

Abstract: According to an exemplary aspect of the present invention, there is provided an apparatus comprising: at least one loudspeaker element, at least one processing core, at least one memory including computer program code, the at least one memory and the computer program configured to, with the at least one processing core, cause the apparatus to produce sound via the loudspeaker element, wherein the at least one processing core is configured to adjust the sound according to criteria stored in the at least one memory, wherein the criteria comprise a wide bandwidth roll-off using at least one parametric shelving filter.

Abstract: According to an example aspect of the present invention, there is provided a method for forming a binaural filter for a stereo headphone in order to preserve the sound quality of the headphone, whereby the sum of the direct and crosstalk paths from loudspeakers to each ear have flat magnitude responses.

Abstract: According to an example aspect of the present invention, there is provided a Method for regularizing the inversion of a stereo headphone transfer function for headphone equalization, characterized by using the equation for the equalization: H S ? ? 1 - 1 ? ( ? ) = H * ? ( ? ) ? H ? ( ? ) ? 2 + ? ^ ? ( ? ) ? D ? ( ? ) = H * ? ( ? ) ? H ? ( ? ) ? 2 + [ ? ? ( ? ) + ? 2 ? ( ? ) ] ? D ? ( ? ) . in which equation HSI?1(?) is sigma inversion H*(?) is complex conjugate of a response D(?) is a delay filter introduced to produce a causal inverse HRI?1(?) H*(?) a response ?(?) is headphone reproduction bandwidth, ?(?) an estimation of the regularization needed inside that bandwidth.

Abstract: According to an example aspect of the present invention, there is provided a method for calibrating a headphone including an amplifier with a memory and signal processing properties, the method comprising steps for determining a desired sound attributes for the headphone, and setting signal processing parameters in the amplifier in order to obtain the desired sound attributes either by measurement or based on the received input information from a user of the headphones.

Abstract: According to an exemplary aspect of the present invention, there is provided an apparatus comprising: at least one loudspeaker element, at least one processing core, at least one memory including computer program code, the at least one memory and the computer program configured to, with the at least one processing core, cause the apparatus to produce sound via the loudspeaker element, wherein the at least one processing core is configured to adjust the sound according to criteria stored in the at least one memory, wherein the criteria comprise a wide bandwidth roll-off using at least one parametric shelving filter.

Abstract: The invention relates to a method and a loudspeaker for storing equalization settings in an active loudspeaker including a loudspeaker cabinet, at least one driver connected to the cabinet and an amplifier electronics including an equalizer, in which method the loudspeaker is calibrated in controlled conditions for forming factory calibration parameters for controlling the equalizer, the factory calibration parameters controlling the equalizer are stored in the amplifier electronics. In accordance with the invention the factory calibration parameters are also stored in a memory fixedly mounted to the loudspeaker.

Abstract: According to an example aspect of the present invention, an apparatus is provided comprising at least one processing core and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processing core, cause the apparatus at least to present a graphical user interface comprising a spatial representation and at least one element, the element being associated with at least one specific physical loudspeaker, and receive input concerning moving of the at least one element within the spatial representation, activate a sensory signal in a physical loudspeaker associated with the first element, determine a location in the spatial representation where the first element is moved to, and based at least in part on the determined location, assign a name to at least the first element and the physical loudspeaker associated with the first element.

Abstract: According to an example aspect of the present invention, an apparatus is provided comprising at least one processing core and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processing core, cause the apparatus at least to present a graphical user interface comprising a spatial representation and at least one element, the element being associated with at least one specific physical loudspeaker, and receive input concerning moving of the at least one element within the spatial representation, activate a sensory signal in a physical loudspeaker associated with the first element, determine a location in the spatial representation where the first element is moved to, and based at least in part on the determined location, assign a name to at least the first element and the physical loudspeaker associated with the first element.

Abstract: The invention relates to a method and a loudspeaker for storing equalization settings in an active loudspeaker including a loudspeaker cabinet, at least one driver connected to the cabinet and an amplifier electronics including an equalizer, in which method the loudspeaker is calibrated in controlled conditions for forming factory calibration parameters for controlling the equalizer, the factory calibration parameters controlling the equalizer are stored in the amplifier electronics. In accordance with the invention the factory calibration parameters are also stored in a memory fixedly mounted to the loudspeaker.

Abstract: The present invention provides a novel drive unit mounting arrangement, in which a drive unit having a chassis is mounted to a cabinet from at least two sides. The arrangement comprises a member for securing the drive unit to the cabinet from mounting points of the chassis. The arrangement further comprises a suspension member between the mounting points of the chassis and the cabinet such as to suspend the drive unit chassis elastically to the cabinet for allowing suspension in both forward and rearward directions.

Abstract: The present publication describes a calibration method and apparatus, in which an electrical calibration signal is formed, an audio signal is formed in the loudspeaker from the calibration signal, the response of the audio signal is measured and analyzed, and the system is adjusted on the basis of the measurement results. The calibration signal is formed in the loudspeaker in such a way that it is essentially a sinusoidal signal, the frequency of which scans at least substantially through the entire audio frequency range.

Abstract: The present invention provides a novel drive unit mounting arrangement, in which a drive unit having a chassis is mounted to a cabinet from at least two sides. The arrangement comprises a member for securing the drive unit to the cabinet from mounting points of the chassis. The arrangement further comprises a suspension member between the mounting points of the chassis and the cabinet such as to suspend the drive unit chassis elastically to the cabinet for allowing suspension in both forward and rearward directions.

Abstract: A method and apparatus in a sound-reproduction system, in which method an electrical calibration signal is formed, an audio signal is formed in the loudspeaker from the calibration signal, the response of the audio signal is measured and analysed, and the loudspeaker system is adjusted on the basis of the measurement results. The operator is permitted to made additional alterations to the settings of the loudspeaker system on the basis of the measurement performed, the effects of the alterations are calculated and displayed to the operator without additional measurements, and the additional settings are implemented in real time in the loudspeaker system.