The Research Of Adaptive Sound Field Balance Control System

Based on the adaptive filtering principles, several typical adaptive filteringalgorithms and its application were introduced. The performance characteristics of thealgorithm was analyzed and compared, and these performance characteristics wereanalyzed based on adaptive filtering algorithm. In response to noise processing method,the LMS adaptive filtering algorithm under the minimum mean square criterion wascarried out. The adaptive filter can meet some best requirements of the guidelines byautomatically adjusting the parameters of itself. In order to further improve the quality ofstereo sound reproduction system, the new algorithm improved the convergence factor onthe basis of traditional least mean square algorithm to make it change depending on theinput signal, and avoid the contradiction between convergence and steady state error. Atlast verifies the effectiveness of the algorithm by Matlab simulation.In order to adjust the room acoustic frequency response curve, a sound field balancecontrol software was designed. The software can compensate for certain low frequencycomponents of the sound field parts, also can inhibit certain parts of high frequencycomponents ranges to make corrections for frequency distortion which was produced bythe audio equipment, to ensure the frequency characteristics of the room straight. Thesoftware can regulate the sound pressure level by positive and negative12dB, in order toimprove the frequency distortion which was caused by the room standing wave or soundabsorption characteristics.Based on the platform of stereo sound system, audio editing software REW was usedas the audio testing tool, use editing feature of the A-A software to mix the signals of thetwo channels together, in order to receive audio signals which was polluted by noise.Filtering the original signal of the noise-containing using adaptive filtering method, andput the filtered signal into the equalizer control software of the sound field, to adjust thesignal of each frequency band. The sound which played by the Lowther full frequencysound system platform is coming from the professional sound card (MAYA44) inside thecomputer, by the way of coaxial output and verifies the effectiveness of algorithm andsoftware by experimental results. Compared with the CD playback sound source, thestereo system platform can remove the inherent noise of the signal source itself, also canprovide more music playback formats and can improve the ADC sampling frequency andquantization level to further increase the sound playback quality, so the application is more extensive.