I've been trying to transform a relatively noisy sound source into pure pink noise (or white noise, for that matter). With this I mean a way to modify the energy distribution of the source sound to gradually approach a pure noise spectrum.
I've tried spectral morphing, but as is typical to FFT it sounds too full of artifacts/artificial (I'm looking for a more 'natural' sounding approach); I've also toyed with various configurations of delay feedback + distortion + filters but this has only a limited effect on the spectrum and a quite different character (more 'crunchy' than the 'hiss' of noise, if you know what I mean)
In the end I'm just looking for a way to 'noisify' an already noisy sound source. Any ideas, techniques or suggestions are welcome.