I'm studying Short-time Fourier Transform and I learned that if you apply a windowing other than rectangular, you need to overlap the frames---for example, 50% overlap for Hamming family---to reconstruct the signal properly (like add them up to 1). However, I only need to apply this window function during the Analysis part and I can reconstruct the signal properly during synthesis.
But in some literature (like Audacity's Noise Reduction) I saw some methods that apply a second window function during the synthesis part and employ a 75% overlap-add. What's the advantage of doing the window function twice (analysis/synthesis) with 75% overlap compared to a single window function (analysis) with 50% overlap? I can't seem to find any explanation justifying the advantage between these two windowing techniques.
Edit: I also tried to implement the 75% overlap with Hann window applied on both analysis and synthesis part and I was able to yield a x1.5 of the original signal's amplitude. Did I do it correctly?