Hi dear Audacity Developers,

I am having a little trouble when doing the noise reduction by using noise gating technique. I am doing below steps:

- STFT the
**background noise**with 2048 Hanning window. The Hanning window is shifted by half the size of the window so the overlapping rate is 50%. - Save 2048 power elements(square of the STFT amplitude) resulted in Step 1 as noise profile.
- STFT the
**audio signal**with 2048 hanning window just as in step 1 for the noise. Comparing each STFT power output with the corresponding element in noise profile in Step 2. If it is

larger than the noise profile power element, the gain is 1;otherwise, the gain is 0; - Inverse STFT the result from Step 3.
- Overlap-add the result from Step 4 to recover the signal.

I am implementing this algorithm on FPGA. The result was not very pretty. I have attached the original noisy audio as well as the output audio. Am I missing any important step here? I have checked online that the drawback of spectral subtraction algorithm is remnant noise. Is it the problem I am having right now? How do I to conquer the problem?

Thanks

yong