# FFT Algorithm is Clicking

**URL:** <https://iplug2.discourse.group/t/fft-algorithm-is-clicking/827>\
**Category:** Uncategorized\
**Created:** [26 October 2023 03:27 UTC](https://iplug2.discourse.group/t/fft-algorithm-is-clicking/827 "2023-10-26T03:27:31Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Kallyn](https://avatars.discourse-cdn.com/v4/letter/k/848f3c/32.png) [@Kallyn](https://iplug2.discourse.group/u/Kallyn)\
**Post date:** [26 October 2023 03:27 UTC](https://iplug2.discourse.group/t/fft-algorithm-is-clicking/827/1 "2023-10-26T03:27:32Z")

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Hi!  
I am trying to test out an FFT algorithm (if you saw my previous post then I was able to get it working, yay!) and I am able to get a nice clean output without any clicking. The moment I try to actually process the spectral data, however, I am left with tons of clicks at regular 4096 sample intervals, the value i have set for my fft size. I imagine there is some inconsistency with the phases or something that makes the fft output not line up smoothly. how can I avoid that and get a smooth output from my plugin?

What I have done with the fft analysis is spectral vocoding (through sidechain input), “squaring” the input (which makes a lossy sound), and spectral gate, removing bins that are too quiet. each of these leaves the audio with these clicks. I have heard of using windowing techniques, but is that necessary?

Thanks!  
Kallyn

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**Author:** ![RexMartin2](https://avatars.discourse-cdn.com/v4/letter/r/da6949/32.png) [@RexMartin2](https://iplug2.discourse.group/u/RexMartin2)\
**Post date:** [26 October 2023 21:19 UTC](https://iplug2.discourse.group/t/fft-algorithm-is-clicking/827/2 "2023-10-26T21:19:47Z")

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> [@Kallyn](#):
>
> I have heard of using windowing techniques, but is that necessary?

Absolutely! Process a file in a DAW with your plugin and then look at the rendered waveform afterwords. It will likely have spikes/large discontinuities at the frame boundaries. Windowing and overlapping are typically required on both the FFT input (analysis) AND output (re-synthesis).

Questions like this are better asked on the “DSP and Plugin Development” forum over at KVR. This forum is for iPlug2-specfic questions/issues.