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Last Updated: 20060508, meiMonday, May 22, 11:00 — 13:00
W10 - FILLING THE GAP BETWEEN LOUDSPEAKERS AND ELECTRONICS
Ronald Aarts, Philips Research Laboratories
Mark Dodd, GPAcoustics, KEF & Celestion - UK
Jan Abildgaard Pedersen, Lyngdorf Audio - Denmark
Gerhard Pfaffinger, Harman/Becker Automotive Systems - Germany
Most loudspeakers use a magnet with voice coil, cone, and suspension in a format that has changed little over many decades. In contrast, the digital signal processor (DSP) has only recently become important in loudspeaker systems. The implications of using DSP on signal amplification, equalization, active cross-over design, linearization, and protection are discussed. DSP-based protection may allow the passive transducer to be operated up to the physical limits while handling any audio input with impunity. Nonlinear loudspeaker motor distortion may be reduced by appropriate filter design. The loudspeaker system frequency response, variations in ambient temperature, and softening of suspension materials can be compensated adaptively. Further improvements may be achieved by use of DSP-based crossovers and also by DSP filters correcting, to some extent, the low frequency room response. DSP filters also allow the direction of beams of sound to better cover the audience area. All this gives new degrees of freedom for reducing the enclosure size, increasing the output while maintaining acceptable quality, improving power efficiency, and optimizing the sound reproduction into the 3-D-space. Finally the workshop addresses practical concerns of digital implementations (cost, robustness, simplicity) in loudspeaker products.
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