I'm performing a series of FFTs on windowed extracts of an input signal, to get a frequency spectrum over time. This is for a visualisation - I'd like to keep the window small, so the visualisation is fast-moving and responsive.
I'm only interested in the amplitude. Occasionally, two or more frequencies are close enough that the amplitude flickers wildly with the interference pattern between the two.
What ways are there to reduce this flickering, that will disturb my time-domain responsiveness less than increasing the window length?
(For reference, this is the visualisation - I'm not concerned with the "flashes" when something happens in the audio, but the juddering is not good.)