Hi, speex developers! I'm new to speex, and trying to build a simple echo application. something like this. microphone -> speex encoder -> speex decoder -> speaker I first test it the simple way, microphone -> do nothing -> speaker and this works fine. But when I try to encode speex, and decode it, it works, but some high frequency noise is added. How can I fix it? The noise isn't the microphone <-> speaker positive feedback, cause it doesn't appear when not using speex. I think the code is almost the same as your testenc_uwb.c included in speex distribution, but mine maybe something wrong causing the noise... Source code is here. http://maaash.jp/lab/speex/main.cpp and Windows binaries here. http://maaash.jp/lab/speex/speexecho.zip There's a switch to enable speex in main.cpp #define USE_SPEEX Thanks in advance! # sorry if you see this email twice, cause it doesnt reach myself after 10 hours..