Genelec Oy

Nokia Oyj

Aki M&auml;kivirta

Ari Olavi Varla

Mauri V&auml;&auml;n&auml;nen

Matti Syd&auml;nmaa

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.

Sound reproduction equipment and method for reducing the level of acoustical reflections in a room

A digital audio receiver stores received frames temporarily for decoding and error concealment. A reconstructing block ( ) in the decoder reads stored frames using a read window ( ) wherein the latest received frame (&plus;cnnxt) is undecoded. Decoding is carried out in stages so that the correctness of the current frame ( ) is examined and possible errors are concealed using corresponding data of other frames in the window. Detection of errors is based on checksums ( ) and allowed values of bit combinations in certain parts of the frame. In addition, the receiver maintains an estimate ( ) for the signal's bit error ratio and uses it to control the operation of the error concealment algorithm.

Error concealment in digital audio receiver

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.

Growing community of inventors

Lapinlahti, Finland

Aki Mäkivirta

Growing community of inventors

Lapinlahti, Finland

Aki M&auml;kivirta

Aki Mäkivirta