| Summary: | Digital audio is introducing a bold new sound in consumer audio and home theater systems. Several factors are converging to bring high-end, surround sound audio to mass market buyers: the rise of the DVD and BluRay, new formats for multichannel audio and widespread use of digital signal processors (DSPs) in audio systems. This project looks into the exciting area of using signal processing to enhance the performance of surround speakers. This system automatically measures and corrects the acoustics of the multichannel sound system for the specific room where the system is being set up, compensating for non-ideal room acoustics, loudness of program and speaker response.
For the objective of this project, the author was more focused on psychoacoustic response of the human ear, volume gain control based on the ambient power level in the room.
Two applications were developed. The first application was the Minimum Volume Control. This application used an 8-band equalizer and the signals are analyzed by FIR band filters. Depending on the power of the signal in the input on the frequency spectrum, the corresponding band gain was decided for the affected bands which controlled the overall volume based on the current noise and signal loudness. The second application tracks the volume of the room and increase or decrease accordingly.
All the applications were developed using SDK VisualDSP++ 5.0 for Blackfin Processors. The FIR filters were designed using MATLAB’s FDATool. The applications were tested on the BF-561 EZ-KIT Lite board provided by Analog Devices.
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