where is noise located

Is noise in the system, the channel, the observer, or the cut between them? Patterns — and therefore noise — are relative to information-processing dynamics: observer-dependent without being merely subjective. What counts as noise depends on what the apparatus is built to notice, which folds this straight into Umwelt and makes the interface a device that decides the answer rather than reports it. Not relativism, since the cut is constrained by apparatus and task; but the same fluctuation can be error in one frame and data in another.