Loudspeaker with absorber supply negative feedback to cone movements - has IR radiation source and receiver for intensity equal to function of cone position

摘要

A loudspeaker which has an absorber for the movement of a cone. The absorber wil supply negative feedback signal which represent the instantaneous position, speed or acceleration of the loudspeaker cone. The absorber consists of an infra-red radiation source (5) and an infra-red radiation absorber (7) which are attached in such a way that the intensity of the infra-red radiation reaching the absorber will be a function of the position of the cone. The radiation source and absorber are tuned for a small frequency spectrum. The absorber and source are attached in such a way that one will be stationary relative to the frame of the loudspeaker and the other will be stationary relative to the cone of the loudspeaker. The intensity reaching the absorber will be dependent on the instantaneous displacement between the source and the absorber.