On Mon, 10 May 2021 15:51:38 +0200 Fons Adriaensen <f...@linuxaudio.org> wrote:
>On Mon, May 10, 2021 at 03:17:12PM +0200, Jeanette C. wrote: > >> There are numerous audiofiles around containing one single cycle wave to >> be used with multiple wavetable synthesizers, both in hard and software. >> I can only assume that these are matched to the number of samples they >> contain. Some of them CERTAINLY proclaimed this fact, > >OK. In that case the actual frequency will be R / N where R is the sample >rate and N the length in samples. This is very probably not exactly an >musical pitch in the equally tempered scale, but that doesn't matter >since the wavetable synth will have to resample it anyway. > >So in this case, all you need is an FFT with a size equal to the lenght >of your single cycle sample. There is no faster method. > >I just checked, FFTW3 can do any size. > >Normally you'd just use the real-to-complex fft. For prime lengths, this >may become slower than normal (N^2 complexity instead of N log N). If this >matters (it probably won't), you could use the complex-to-complex fft with >the imaginary part set to zero, this will be faster (always N log N). > >In all cases, the N / 2 + 1 first elements of the output will correspond >to the harmonics, so you just the square root of the power of each. > >Ciao, > Not entirely clear on what you are doing, but you may find PadSynth the be a better option. It already creates perfectly looping samples (not sure if you can fiddle that for a single cycle) and will then export these over as a number of different pitches/key numbers. -- Will J Godfrey https://willgodfrey.bandcamp.com/ http://yoshimi.github.io Say you have a poem and I have a tune. Exchange them and we can both have a poem, a tune, and a song. _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org https://lists.linuxaudio.org/listinfo/linux-audio-dev