Bang and Olufsen A/s

Harman Becker Automotive Systems Manufacturing Kft

Sl Audio A/s

Harman Becker Gepkocsirendszer Gyarto Korlatolt Felelossegu Tarsasag

Jan Abildgaard Pedersen

Ole Ploug

Martin Olsen

Martin Bo Møller

Patrick James Hegarty

Philip Coleman

Philip Justin Bletsoe Jackson

Marek Olik

Disclosed are methods for selecting auditory signal components for reproduction by means of one or more supplementary sound reproducing transducers, such as loudspeakers, placed between a pair of primary sound reproducing transducers, such as left and right loudspeakers in a stereophonic loudspeaker setup or adjacent loudspeakers in a surround sound loudspeaker setup. Also disclosed are devices for carrying out the above methods and systems of such devices.

Multichannel sound reproduction method and device

The present invention relates to methods and systems for determining an equalization filter for one or more loudspeakers provided in an enclosure, such as a listening room or an automobile cabin. A method for determining an equalization filter for one or more loudspeakers provided in an enclosure comprises the steps of providing the one or more loudspeakers with an audio input signal whereby a sound field is generated in the enclosure; determining an acoustic contribution or room gain of the enclosure to the generated sound field; forming a speaker equalization filter as the square root of the ratio between a target acoustic power output and the actual acoustic power output from the loudspeaker driver(s), which actual acoustic power output is calculated as the square of the power averaged sound pressure divided by the room gain; and determining the equalization filter as the speaker equalization filter.

Adaptive sound field control

The invention relates to a method and a system for adapting a loudspeaker to a specific listening position relative to the loudspeaker according to which method and system the acoustic power radiated by the loudspeaker is corrected by means of a correction filter inserted in the signal path through the loudspeaker, the response of said correction filter being determined by comparison between the a quantity characterising the radiated acoustic power measured at an actual listening position and a similar quantity measured at a reference listening position. According to a specific embodiment of the invention said characterising quantities are the radiation resistances measured at the actual listening position and the reference listening position respectively.

Method and system for adapting a loudspeaker to a listening position in a room

Disclosed is a method for equalizing a first loudspeaker positioned in a room in order to compensate for an influence of the room, the method comprising the steps of 1) measuring a listening position transfer function from electrical input of the first loudspeaker to a sound pressure at a listening position in the room, 2) determining a global transfer function representing a spatial average of sound pressure level in the room generated by the first loudspeaker, 3) determining an upper gain limit as a function of frequency, the upper gain limit being based on an inverse of the global transfer function, 4) determining an equalizing filter based on an inverse of the listening position transfer function, wherein a gain of the equalizing filter is limited to a maximum gain in accordance with the upper gain limit, and 5) equalizing the first loudspeaker according to the equalizing filter.

Method and system for equalizing a loudspeaker in a room

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.

Environment adaptable loudspeaker

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. Based on the above measurements, the ratio between the radiation resistances, radiated power or real part of the acoustic wave impedances is determined, and the ratio, optionally after suitable further processing, is used to control a controllable correction filter inserted in the signal path of the loudspeaker, whereby the performance of the loudspeaker in the second acoustic environment can be brought substantially to match the performance of the loudspeaker in the first acoustic environment.

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Holstebro, Denmark

Jan Abildgaard Pedersen