Abstract: A nested compound loudspeaker comprising a speaker assembly chassis (11), an outer driver (18) connected to the speaker assembly chassis (11) and having an inner edge, which defines an opening in the outer driver (18) and forms a functional edge (20), and an inner driver (8) connected to the speaker assembly chassis (11) and at least partially surrounded by the opening of the outer driver (18) and the inner driver (8) having an acoustical centre axis located at a distance (r) from the functional edge (20) in a radial direction (?). The distance (r) is non-constant around the acoustical centre axis, wherein the distance (r) has a first value in a first radial direction (?) and a second value different to the first value in a second radial direction (?).

Abstract: A method and apparatus for attenuating acoustic reflections related to sound radiated by a loudspeaker in an acoustic space. According to the method, at least one cancelling loudspeaker is used for radiating a canceling sound in the space. The signal required for producing the cancelling sound is sampled from the sound reproduction apparatus prior to the processing of the original sound signal for emission into the acoustic space. The sample signal is low-pass filtered, delayed, amplified and inverted prior to being taken to the cancelling loudspeaker. The sound reproduction apparatus includes a signal sampling device, control devices, and at least one cancelling loudspeaker for radiating the cancelling sound.

Abstract: The present invention concerns the reduction of vibrations of a loudspeaker enclosure caused by the mechanical vibrations of the dynamic loudspeaker element by virtue of attaching one or more additional masses to the loudspeaker driver unit using elastic and lossy means. The masses with their elastic attachments dimensioned according to the present invention resonate at frequencies excited by the vibrations of the loudspeaker element at frequencies where the reduction of the amount of vibration is desired. The magnitude of vibration coupled to the enclosure of a loudspeaker modified according to the present invention is significantly smaller than that of a conventional loudspeaker. Furthermore, it is technically and economically advantageous to implement the reduction of mechanical vibrations according to the present invention.