Windowing real time audio data for FFT

Question

How does one window audio data for an FFT to avoid leakage across buffers and what is a superior window for this task?

I currently read 1024 samples from the microphone and can apply a window, but am unsure on how to carry these windows across buffers and how to add padding when needed so that there is no spectral leakage.

Are circular buffers used for this?

If audio is a constant signal during its lifetime and we sample it in buffers of 1024 samples and run these buffers through a FFT, will there not be inconsistencies is the accuracy if a window is only applied to each buffer? I'm imagining a window that runs over the edge of a buffer and into the start of the next, so that data between buffers is connected. — some_id
What are you doing with the FFT? Displaying, filtering, something else? — Jason B

hotpaw2 hotpaw2 · Accepted Answer · 2014-03-26T00:58:36

There is always so-called "spectral leakage" for any finite length FFT frame or signal. Zero-padding won't eliminate it.

Windowing real time audio data for FFT

1 Answers