Howl
August 18, 2020, 1:09pm
12
Here’s a little more details about that FFT Size parameter: I usually explain it as the equivalent of focus in photography.
Imagine a lens with a wide aperture, you can’t get every depth in focus at once, you have to choose your subject.
The same goes for the FFT Size, it’s a focus control which instead of choosing a certain depth, choose a certain time/frequency balance.
The smaller the FFT Size, the more details you’ll get with time-centric events (such as transient sounds) but the blurrier the tones.
The larger the FFT Size, the more details you’ll get with frequency-centric events (such as static tones) but the blurrier the transients.
However spectrograms are not just transients and static tones, there’s a wide variety of frequency shapes in a recording.
See the spectrogram of a voice for instance : it’s a lot of frequencies stacked on top of each others, which are not just straight lines but wobbling lines. Which means they are not purely horizontal or purely verticals, but a mix of both, and they vary over time. So sometime you need to focus on the horizontal parts, sometime on angled parts, sometime verticals, sometime curves, etc.
A picture being worth a thousand words, here’s the same example under 3 different FFT Size (see the parameter at the top right of the screen):
https://i.imgur.com/y47vR5T.png
https://i.imgur.com/PEah3Pe.png
https://i.imgur.com/EjTkm5D.png
thanks! i thought while i was writing the other post, or thought, the word “transient” came up in my mind. but because i didn’t know it for sure… and the word “time”, and yes, there is more to it. you explain it well!
i will print this… perhaps worth a special paragraph (with the pictures) in the manual!
or print this, save this: i am dutch, i am cheap…
very worthfull information to work with spectralayers!