Loudspeaker

About: Loudspeaker is a research topic. Over the lifetime, 14114 publications have been published within this topic receiving 104660 citations. The topic is also known as: speaker & Refoam.

Wireless and wired speaker hub for a home theater system

Abstract: A method and system for communicating audio, video, and/or control signals within a home entertainment system. A plurality of audio channels is communicated between a wireless transmitter and a wireless receiver. The wireless transmitter is located proximate to a speaker housing. In some embodiments the speaker housing also encloses a center channel loudspeaker. The center channel loudspeaker transmits an audio signal to a remote loudspeaker. An exemplary remote loudspeaker is a subwoofer loudspeaker. The subwoofer loudspeaker provides one or more received audio channels to one or more surround loudspeakers.

Fundamentals of binaural technology

Abstract: This article reviews the fundamental ideas of the binaural recording technique. A model is given that describes the sound transmission from a source in a free field, through the external ear to the eardrum. It is shown that sound pressures recorded at any point in the ear canals—possibly even a few millimeters outside and even with a blocked ear canal—can be used for binaural recordings, since they include the full spatial information given to the ear. The sound transmission from a headphone is also described. It is shown how the correct total transmission in a binaural system can be guaranteed by means of an electronic equalizing filter between the recording head and the headphone. The advantage of an open headphone is stated. It is shown that a certain degree of loudspeaker compatibility can be achieved, if the equalizer is divided into a recording side and a playback side. A method for true reproduction of binaural signals through loudspeakers is also described. A number of topical and prospected applications of binaural technology are mentioned. Some of these utilize computer synthesis of binaural signals, a technique which is also described.

Active adaptive sound control in a duct: A computer simulation

Abstract: Most active sound cancellation systems reported in the literature use open‐loop control, depend on near‐zero phase delay in control system elements, and require constant acoustic signal transit time from a signal pickup (microphone) to a control sound source (loudspeaker). The applicability of such systems can be significantly enhanced by using closed‐loop control. This study concerns a digital computer simulation of adaptive closed‐loop control for a specific application, sound cancellation in a duct. The key element is an extension of Sondhi’s adaptive echo canceler and Widrow’s adaptive noise canceler from signal processing to control. The adaptive algorithm is thus based on the LMS gradient search method. The simulation shows that one or more pure tones can be canceled down to the computer bit noise level (−120 dB). In the presence of additive white noise, pure tones can be canceled to at least 10 dB below the noise spectrum level for SNR’s down to at least 0 dB. The underlying theory implies that the algorithm allows tracking tones with amplitudes and frequencies that change more slowly with time than the adaptive filter adaptation rate. The theory implies also that the method can cancel narrow‐band sound in the presence of spectrally overlapping broadband sound. The method can be applied more widely, particularly to control systems that involve transport delay.

Reproduction of a plane-wave sound field using an array of loudspeakers

Abstract: Reproduction of a sound field is a fundamental problem in acoustic signal processing. In this paper, we use a spherical harmonics analysis to derive performance bounds on how well an array of loudspeakers can recreate a three-dimensional (3-D) plane-wave sound field within a spherical region of space. Specifically, we develop a relationship between the number of loudspeakers, the size of the reproduction sphere, the frequency range, and the desired accuracy. We also provide analogous results for the special case of reproduction of a two-dimensional (2-D) sound field. Results are verified through computer simulations.