Abstract: The invention relates to a projector screen having a projection surface essentially forming a spheric section, comprising a rigid structure (1) that is preferably male of a metal, and a membrane (2) that is preferably made of a textile, the membrane being supported by said rigid structure (1), characterised in that the membrane (2) envelops the rigid structure (1) and in that a means (3) for generating a vacuum is provided in order to keep the membrane (2) pressing against the rigid structure (1). Application to screening rooms.

Abstract: The device according to exemplary embodiments of the invention includes means for compensating the effects of temperature for cells that are used to obtain reverberation effects in an auditorium. This avoids the disagreeable effects of the “Larsen” effect, for example. The invention may be applicable to a public address system in a concert hall.

Abstract: An extracting assembly for extracting a component signal generated by a component source from a composite signal is disclosed wherein a reference sensor generates a reference signal relating to activity of the component source, a composite sensor senses the composite signal, an adaptive filter is operatively connected to the reference sensor and the composite sensor to filter the component signal from the composite signal as a function of the reference signal generated by the reference sensor, and a normalizer operatively connected to the adaptive filter for normalizing the step size of each iteration taken by the adaptive filter to minimize the time to adapt the adaptive filter to transform the reference signal into the component signal.