hard off wrote: > ah cheers frank, thanks for clearing a lot of that up. you do really > good explainations. > > > "The main reason we use complex numbers in electronic music is > because they magically automate trigonometric calculations. We > frequently have to add angles together in order to talk about the > changing phase of an audio signal as time progresses (or as it is > shifted in time, as in this chapter). It turns out that, if you > multiply two complex numbers, the argument of the product is the sum > of the arguments of the two factors." > > so, is that where 'fast' fourier transform comes from then?
Not really, as multiplication is one mathematical operation. 'Fast' in FFT means reducing the number of mathematical operation from O(N²) to O(N log N), where N is the number of analyzed frequencies, e.g. for 64 frequencies from (a constant factor times) 64²=4096 to (another constant factor times) 64 * log(64)~116 operations. cu Thomas -- "Prisons are needed only to provide the illusion that courts and police are effective. They're a kind of job insurance." (Leto II. in: Frank Herbert, God Emperor of Dune) http://thomas.dergrossebruder.org/ _______________________________________________ PD-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list