APLODSP, design of customizable Audio Processor for LOudspeaker system compensation by DSP

This paper summarizes the results of the ESPRIT project APLODSP. The goal of this application experiment is to develop adequate models for the simulation of the non-linear behavior of loudspeakers and to design a dedicated audio processor to reduce sound distortion. This involves the definition of a systematic design flow for anti-distortion audio processors, and the effective exploitment of CAD tools for the automatic implementation of the defined algorithms. The audio processor will be implemented with a DSP, using state-of-the-art tools for simulation, validation and synthesis. DSP is the emerging low cost technology for audio processing, and in particular for car-audio systems. In fact, car manufacturers are planning to reduce the cables inside the car and to use a single cable to distribute the main signals multiplexed all around the vehicle. This transition to digital audio signal transmission will foster the use of active loudspeakers, equipped with dedicated digital audio processors. The audio processor, designed and tested within this ESPRIT project, can be seen as a first step in this direction. It shows how the loudspeaker distortion can be reduced by digital signal processing, and it exploits the versatility of digital designs in order to allow hardware re-use for different car models. It also allows a very fast redesign to fit many different purposes. A semi-automatic design flow for the design of anti-distortion audio processors is available, which synthesizes a dedicated audio processor for each loudspeaker model, once suitable loudspeaker parameters have been specified.