Celestion SL600si loudspeaker & DLP600 digital equalizer Digital Audio Filters
There has been considerable published work in recent years on the use of filters operating in the digital domain to optimize loudspeaker performance. Those interested should read the following papers: "Efficient Filter Design for Loudspeaker Equalization," Richard Greenfield and Malcolm O. Hawksford, JAES Vol.39 No.10, October 1991; "Digital Equalization Methods for Audio Systems," J. Mourjopolis, and "Application of Digital Filters to Loudspeaker Crossover Networks," Rhonda J. Wilson, J.B. Scott, and the late Glyn J. Adams, both presented at the 84th AES Convention, March 1988, Preprints 2598 and 2600, respectively; "Digital FIR Filters for Loudspeaker Crossover Networks," Peter L. Schuck and Greg Klowak, and "Amplitude and Group Delay Control Using a Digital Equalizing Processor," Masaharo Matsumoto et al, both presented at the 85th AES Convention, November 1988, preprints 2702 and 2692, respectively. (Preprints are available from the Audio Engineering Society, 60 East 42nd Street, New York, NY 10165, and cost $5 each to nonmembers, including postage and handling.)
Celestion's Research Director, Graham Bank, has also published a paper on the design of the DLP600, "The Implementation of a Digital Loudspeaker Processor for the Celestion SL600/SL600Si," which should be available from Celestion at the address given in the specification sidebar.
The most accessible book I have come across on the design and understanding of digital filters is Discrete Time Signal Processing by Alan V. Oppenheim and Ronald W. Schafer (Prentice-Hall, 1989).—John Atkinson