A Moogle  🏳️‍🌈 💻 🎮 🎶 🇸🇪

Right, I've been trying to work this out for about 3 hours now. I feel like I'm on the cusp of understanding but just need a straightforward answer from someone knowledgeable in audio-related maths. I'll reply to myself with the problem since I've run out of space in this tweet.

I have an FFT of size S (thus S/2-1 bins), and a Nyquist frequency of F. I want to display a spectrum analyzer with B bars. Given these, how do I calculate the number of FFT bins to combine for each bar from 0 to B-1?

If you have a real FFT, there should be S/2+1 bins (S/2-1 complex frequencies + 1 real DC + 1 real nyquist). I’ve done this multiple times and it never looks particularly great. My usual approach is to assume each edge has a bin index of A exp(B n) ...

Where n is the band index. A and B are derived to ensure that the final band index gives the last bin index and that the low bands use more than one bin.