from curtis road’s microsounds:
“As a preparation for spectrum analysis, the STFT imposes a window upon theinput signal. A window is nothing more than a simple amplitude envelope. Windowing breaks the input signal into a series of segments that are shaped inamplitude by the chosen window function and bounded in time according tothe length of the window function. In audio applications, the duration of thewindow is usually in the range of 1 ms to 100 ms, the window envelope is bell-shaped, and the segments usually overlap. By analyzing the spectrum of eachwindowed segment separately, one obtains a sequence of measurements thatconstitute a time-varying spectrum.” (page 246)
in one thread about pitch shifting vocals;
you also use a resolution setting, is the resolution setting more overlapping segments/windows??
it seems the resolution setting also effects the result??? not mentioned in the manual.
i try to understand it, i can follow what curtis road writes. but to reproduce by heart, i can not.
i think it perhaps important to know more what is under the hood, for a better understanding of what one can do in SpectraLayers, and how to inteprete.
curtis road goes further, with Phase Vocoders, and ends (not really) with Metasynth. a quite different approach or not?
drawing a harmonic, with 5 harmonics on top… wel… o well not to the point at this moment…
the FFT size; a FFT size of 4096 (for example) means N/2 bin’s, N is the sample rate, only half of the samples is used, because of Nyquist. so for a FFT size of 4096, 2048 bin’s are used, with amplitude, frequence and start phase (of the sine). the others are ignored.
curtis road also states that a higher sample rate, does not increase frequency resolution, which now i write, is completely understandable, for me now, tomorrow not.
i am an enthuastic student, and when i know more about how something works under the hood, and even if i understand weakly, or just… i can incorporate it, and master a program or synth better.
(i found this in microsounds, because of my great interest in granular, and i have a great interest in spectral, there is a chapter about it, i didn’t notice it before, because, this book, was out of my league, but i can read it now, still above my paygrade, but more accessible. perhaps i dive to deep, and just must do things. but i do! but deep diving, gives me also results, better results…
so maybe not the best book about STFT/FFT/PV etc. or maybe it is a good intro for it…)
o yes, from the quote above:
" A window is nothing more than a simple amplitude envelope.",
the blackman-harris, hanning, etc. options. indeed changes a spectrogram, more visible i feel in a spectroscope, you see different results. but i don’t really have worked with different ‘windows’, because they are sometimes also called windows. all those therms, or jargon…
the amplitude shape can give different results. visually but also audible??
i hope i more clear now…