4.4 A LOUDSPEAKER MANAGEMENT SYSTEM WITH FIR/IIR FILTERING
RAINER THADEN(1), SWEN MÜLLER(2), GOTTFRIED BEHLER(3), ANSELM GOERTZ(1), MICHAEL MARKARSKI(1), JOCHEN KLEBER(4)
(1) Four Audio GmbH & Co. KG, Aachen, Germany. (2) Divisão de Acústica, INMETRO, Xerém, Brazil. (3) Institute of Technical Acoustics, RWTH-Aachen University, Germany, (4 )Camco GmbH, Germany.
Most digital loudspeaker processor systems use cascaded IIR filters to perform the crossover function and system
equalization. This work presents a multirate platform which allows FIR and IIR filters to be freely combined in each
output channel. The pros and cons of both filter types are discussed and some techniques to obtain suitable FIR
filter coefficients are described. Dual-range AD conversion satisfies the need for high dynamic input range, while
look-ahead peak-limiters in the outputs avoid clipping and mechanical damage without introducing noticeable