A few questions regarding FFT Frequency about csharp-data-visualization HOT 1 CLOSED

This repository has numerous frequency-related projects:
https://github.com/swharden/Csharp-Data-Visualization

For simplicity, I will focus on this one:
https://github.com/swharden/Csharp-Data-Visualization/tree/master/projects/17-07-16_microphone

1. Presumably, although I haven't spent much time on .Net core. It's a relatively simple math process (the FFT) which is used in lots of tasks, so I imagine it's easy to get going in .Net core even if it requires a different library.
2. frequency range goes down to 0, and low bass will register
3. windowing is useful, and is applied. The window is applied here

   Csharp-Data-Visualization/projects/18-01-11_microphone_spectrograph/WindowsFormsApp1/WindowsFormsApp1/Form1.cs

   Line 114 in e76559c

   fft_buffer[i].X = (float)(unanalyzed_values[i] * FastFourierTransform.HammingWindow(i, fft_size));

4. To narrow the number of frequencies, decrease the number of values you feed to the FFT function. You will always get 1/2 the number of values out of the FFT as you put in. Alternatively, you could get more frequencies out than you need and then bin and average them.

PS: you may find this useful:
https://github.com/swharden/Csharp-Data-Visualization/blob/master/notes/FFT.md

Best!
Scott

from csharp-data-visualization.