alan.b.pearce@stfc.ac.uk wrote: > What sort of time delay would this introduce? Without experience of > doing this way, it seems to me from your description that it would be > 100mS, but am probably way off the mark. A total of 100ms of sound is stored, but that need not be the delay. In fact in this case it will have no function on the delay since there is no reason to have the filter kernel extend to future time. Put another way, the 100ms of stored sound is there to cancel the echos produced by that sound. The system passes what it picks up minus what it thinks are echos o= f old sounds. There will also be some frequency shaping and other stuff so there's more going on than echo cancelling, but that's a conceptually simpl= e way to think of it. ******************************************************************** Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products (978) 742-9014. Gold level PIC consultants since 2000. --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .