First, I have one more project: -Overview file format for libsndfile; e.g., (min,max,rms) per block; the overview file would be used, e.g., for fast waveform drawing Then, thanks. I will check the pitch detectors you have. I have collected papers on pitch detectors if you want take a look at them -- I will check too, of course. Do you know how your code could be changed to the formant detector? It must be a harder project. Two first formants should be tracked. Juhana -- http://music.columbia.edu/mailman/listinfo/linux-graphics-dev for developers of open source graphics software