Hey guys, I need some help getting Speex Echo canceller to work. My playback and recording are async. So I plan to use: speex_echo_playback(echo_state, echo_frame); speex_echo_capture(echo_state, input_frame, output_frame); I am able to capture sound from mic at 8000 16 bits mono with 320 bytes per iteration. But I have no idea what the above parameters will I use (I also have no idea what values make sense to setup the EchoStates according to the format and the data size). Would you suggest some value? I saw your testecho sample which uses 128, and 1024. But that doesn't work for me (I got access violation) Million thanks YUN TAO HAI