Notes
Outline
Inverse numerical filters for linearisation of loudspeaker’s response
A. Farina, E. Ugolotti, A. Bellini, G. Cibelli, C. Morandi
Outline
Loudspeaker physical conformation;
Loudspeaker non-linear modeling;
Digital audio Processor for distortion compensation;
DSP implementation;
Measured distortion results;
Basic loudspeaker conformation
Loudspeaker modeling
Loudspeaker modeling
Loudspeaker non-linear modeling
Mathematical formulation
Audio processor
DSP implementation
DSP implementation
 Audio processor implemented with a 320C54x  DSK;
 40 MIPS, 10Kword Dual Access RAM;
 Sampling frequency 23148 Hz;
 Converter resolution 14 bit.
Multirate Audio processor
Audio processor measurements
Response (SPL) Results
Distortion (THD) Results
Distortion (THD) Results
Conclusions
Definition of a non-linear model for low frequency loudspeaker systems;
Design of a parametric audio processor for the compensation of non-linear distortion of loudspeaker;
 Implementation of the audio processor with a low cost commercial DSP;
 Measured reduction of Distortion with the insertion of the audio processor;
The future
New Hardware (Analog Devices SHARC on the EZ-KIT stand-alone board)
Inverse filters computed with the Kirkeby regularization technique
Full-band linearization by means of “warping” instead of dual-band processing
The inverse filter will include also the acoustics behaviour of the car compartment