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Asked: 2026-06-05T08:08:42+00:00

I am using the Jtransforms library which seems to be wicked fast for my

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I am using the Jtransforms library which seems to be wicked fast for my purpose.

At this point I think I have a pretty good handle on how FFT works so now I am wondering if there is any form of a standard domain which is used for audio visualizations like spectograms?

Thanks to android’s native FFT in 2.3 I had been using bytes as the range although I am still unclear as to whether it is signed or not. (I know java doesn’t have unsigned bytes, but Google implemented these functions natively and the waveform is PCM 8bit unsigned)

However I am adapting my app to work with mic audio and 2.1 phones. At this point having the input domain being in the range of bytes whether it is [-128, 127] or [0, 255] no longer seems quite optimal.

I would like the range of my FFT function to be [0,1] so that I can scale it easily.

So should I use a domain of [-1, 1] or [0, 1]?

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  1. Editorial Team

    Essentially, the input domain does not matter. At most, it causes an offset and a change in scaling on your original data, which will be turned into an offset on bin #0 and an overall change in scaling on your frequency-domain results, respectively.

    As to limiting your FFT output to [0,1]; that’s essentially impossible. In general, the FFT output will be complex, there’s no way to manipulate your input data so that the output is restricted to positive real numbers.

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