In future tele-conferencing systems, because of wide range communication needs in daily life with multi users talking simultaneously the conventional AEC systems does not give good spatial speech realism. This book describes simple and effective techniques to decoorelate the stereo signals so that correct identification of stereo echo path responses is possible. Implemented a Stereo Echo Cancellation(SEC) system employing signal decorrelation with emphasis Affine Projection Algorithm (APA). The echo path models are simulated using RIR image method. The techniques used for decorrelation are Non linear Processing(NLP) using half rectifiers and Time Varying All pass Filters(TV-APF). The two channel Affine projection Algorithm was used to adapt the echo path responses. The echo path models are simulated using Room Impulse Response(RIR) with image method. This is totally done in MATLAB environment. This echo canceler is set to achieve good spatial communication and speech perception between transmitting and receiving sides where even more than two people talking while moving around with dual microphones setup for communication.The ERLE in case TV-APF was about 40.3231dB which is good.