CODEWITHSUNDEEP
c#.netfftnaudio
Alexander Mashin
Alexander Mashin

Reputation: 711

Frequency of sound FFT

I have one problem. I'm using NAudio, on C#. My Sample rate = 40960. My microphone, give me buffer every 100ms(4096 bytes). I send this to fft. If I look to only 4096 elements, correct to say about sound frequency more than 2048 Hz? Or I need to use for this buffer size more than this?

Upvotes: 1

Views: 1076

Answers (1)

Paul R
Paul R

Reputation: 213170

Your sample rate, Fs = 40960 Hz, therefore your FFT will represent real positive frequencies from 0 to Fs / 2 (Nyquist) = 0 Hz to 20480 Hz.

The resolution of your FFT is Fs / N = 40960 / 4096 = 10 Hz. So each bin is 10 Hz wide, and the first 2048 complex output bins represents frequencies from 0 to 20480 Hz in 10 Hz increments (you can ignore the other 2048 output bins since they contain no additional information for a purely real input signal).

For a more complete explanation see this answer.

Upvotes: 4

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