When I hear white/pink noise looped I can tell that it's being looped, and pick out parts of it even if it's repeating every few seconds. I was wondering if there's a length of noise that we won't notice is being looped.
Technically any periodic/repetitive signal is actually made up of tones, and very short loops of noise are far more tone-like than noise-like. The longer the repetitive loop, the closer together the tones become, and if they are all so close together they are within the critical bands of our hearing then we can't perceive them anymore? But I think I could still hear the random variations in frequency content and notice when it repeats?