Hi,

Is there any external object for cepstrum analysis? or any antorher way to make a cepstrum analysis?

see http://puredata.info/downloads/timbreid

Thanks for your quick reply, i need also autocepstrum (autocorrelation of cepstrum), how can i do this with tId? And do you know how can i detect echo's with this library?

Ask the pd-list, someone will certainly know. As for detecting echoes, i guess that it's fairly easy if you can send a signal test like a short noise burst.