Abstract: The present invention relates to an apparatus and a method for converting power from a power input to a DC output current or voltage, where a first feedback circuit a traditional feedback. The converter type is a resonant DC-DC converter. The scope of the invention is to reach a high effective and fast responding switch mode power supply. This can be achieved with an apparatus or method comprising a second feedback circuit leading a signal from a serial resonance capacitor(s) to a reference input terminal at the control circuit, which second feedback circuit contains a signal depending on the actual change in charge of the resonant capacitor(s). This means that at high load, a very powerful signal will be transmitted through the second feedback at the control circuit that will change the operation of the circuit into a charge mode operation.

Abstract: A loudspeaker assembly is described which assembly may be moved from a non-exposed to an exposed position by suitable means of which a few are discussed. The inventive assembly may comprise an acoustic lens and a particularly advantageous application is for use in an automotive hi-fi system. A number of other applications are also described.

Abstract: It is known to make the performance of a loudspeaker “environment adaptive” in controlling a filter unit based on a measurement of the velocity/acceleration of the loudspeaker diaphragm and the associated sound pressure in front of the diaphragm, by means of an accelerometer and a microphone, respectively, thereby determining the radiation resistance of the diaphragm. The two sensors have to exhibit a constant transfer function throughout the life time of the loudspeaker, which make them very expensive. With the invention it has been found that the accelerometer can be replaced by another microphone held in a small distance from the diaphragm, and this conditions the possibility of using the same microphone for both measurements, e.g. simply by physically moving the microphone from one position to another. It will then no longer be required to use long-time stable sensors, whereby the price of the sensor equipment can be reduced dramatically. Also alternative arrangements are disclosed.

Abstract: A metal structure (1) has a display region being a second region and being integrate with another region being a first region which is a display region. The metal structure may constitute a monolithic structure of an information display unit, for example, a front panel of an electronic device. The display region is formed by providing a cluster of small non-through-going cavities (5) in the metal structure, leaving a very small thickness of material, the thickness being translucent (6). In addition to being a display unit when arranging a light source behind the translucent region (6), touch sensitive or non-touch sensitive input devices, optionally connected to acoustical input and registration devices, may also be provided. These input devices may advantageously be arranged in, or adjacent, the cavities in the metal structure, whereby when the front of the metal structure is viewed an indication of display or input options is visible.

Abstract: A method and corresponding apparatus for controlling the performance of a loudspeaker in a room includes the steps of, in a first acoustic environment, which may be regarded as a reference, determining the acceleration, velocity or displacement of the loudspeaker diaphragm and the sound pressure in front of the diaphragm, and, based on these quantities, determining the radiation resistance, radiated acoustic power or real part of the acoustic wave impedance. Thereafter, the above step is repeated in a second acoustic environment, which will normally be the actual listening room in which the loudspeaker is to be used.