Thank you for your prompt respond. I guess the preprocessor that should do the improvement for us is the echo suppressor. However we found out that we needed to have at least the denoise activated also in order to see any effect at all. We have made an offline run with testecho.c with the preprocessors activated with default settings. We have used the same aec_play/aec_rec file as before and you can find them together with the generated aec_out.sw and out.sw (after preprocessor) here: https://extranet.svep.se/AEC_echotest_Dump_100ms.zip For very short periods in the beginning of the dumped files (i.e. sample 46000-47500) we see that the echo suppressor is doing a good job resulting in a total ERLE of almost 35 dB. However in general we only se about 2-3 dB improvements on ERLE when we activated the preprocessors. Best Regards /Johan Nilsson