This might be interesting to some of you: The newly granted patent US6625629 "System and method for signal processing using an improved convolution technique" owned by Microsoft, covers partitioned convolution. The patent was filed in May 2000, and granted in September 2003. This is in most claims the same convolution algorithm previously patented by Lake Technology with priority date back in July 7 1992, US5502747. And that is in most claims the same algorithm as invented and published by Soo and Pang and others prior to 1992, which is the same algorithm used in my software BruteFIR. Isn't the patent system wonderful? The requirements "new" and "non-obvious" were in practice scrapped a long time ago... Anyway, Microsoft does as far as I know not have the tradition to harass free software developers as Lake has, so I don't think the fact that another one owns the partitioned convolution algorithm will cause any more trouble. It would be interesting to know what Lake thinks about this. If Microsoft has patented it, they probably use it, and then Lake might want them to pay royalty, or else.... /Anders Torger