Abstract: An audible vehicle warning system is arranged for generating a horn signal and includes a loudspeaker system having a loudspeaker arranged for outputting sound signals at least in a selected frequency range comprising at least frequencies from 400 to 2 kHz, a sound library including one or more sound signals intended as a horn signal when output by the loudspeaker. Each of the sound signals has a ? octave frequency band, which is taken as a reference frequency band. The reference frequency band contains at least a predetermined part of the total power of the sound signal. An ? octave frequency band averaged response of the loudspeaker system has in a ? octave frequency band corresponding to the reference frequency band an amplitude level, which is at least a given amount of dB above the average amplitude level in the selected frequency range.

Abstract: A method for positioning a shaker in a seat includes a headrest and a backrest. The headrest has a bass loudspeaker. The shaker is positioned in the headrest. The seat is typically a seat in a motor vehicle or a seat in a theatre or a massage chair or an entertainment chair.

Abstract: A head tracking system for use in a headrest, includes at least one optical circuit having a plurality of sensors. Each sensor arranged to detect light reflected from at least portion of an illuminated scene. The portion of the scene contains at least a part of a head to be tracked, and to provides an output signal corresponding to an amount of reflected light detected by the sensor. An acquisition circuit is arranged to receive a plurality of output signals from the plurality of sensors and to derive a frame from said output signals. A processing unit is arranged to receive the frame and to derive an indication of a change in position and/or orientation of the head by comparing the received frame with one or more frames obtained at different moments in time.

Abstract: A head tracking system for use in a headrest, includes at least one optical circuit having a plurality of sensors. Each sensor arranged to detect light reflected from at least portion of an illuminated scene. The portion of the scene contains at least a part of a head to be tracked, and to provides an output signal corresponding to an amount of reflected light detected by the sensor. An acquisition circuit is arranged to receive a plurality of output signals from the plurality of sensors and to derive a frame from said output signals. A processing unit is arranged to receive the frame and to derive an indication of a change in position and/or orientation of the head by comparing the received frame with one or more frames obtained at different moments in time.