No, I'm saying that the tests in the OP don't measure aliasing, unless something has been done to completely isolate the effect of aliasing (which it plainly hasn't) from any other effects. TrueRTA is a spectrum analyser, not an aliasing analyser.
I believe the "isolating effect" is that the Axe models exclude analog thermal noise from the modeled amp. Not sure what other brands do, but I and probably most other modeling converts do not require an exact replica of all aspects of the amp such that it includes idling high gain hiss or other non musical artifacts of the analog amps. As I mentioned previously, the lack of hiss and hum in my high gain amp blocks and that very low noise floor seems a distinct advantage in my quest for clarity and detail. It's yet another way amp modeling can excede the real thing, like there being no possibility of the preamp oscillating at the highest gain settings
Is there such a thing as an "aliasing analyzer"? I could find no mention of one on the web. A spectrum analyzer is an aliasing analyzer if the only analog thing being inputted into the model and then outputted into said analyzer is a tone going through a digital architecture replicating a high gain amp signal path. As I understand the graph, the only other analog signal in evidence in the graph beyond the 9-11k tone, are the harmonics from the mains voltage. If there were other analog noises mixed into a high gain architecture, like modeled high gain hiss, I think it would be much louder than the harmonics from the mains hum and would show up as something with an amplitude higher than the mains harmonics, but less than the 9-11kz tone. The absence of any higher amplitude/gained up analog noise modeled artifacts and the low Axe noise floor leaves only aliasing, right?
You'd be quite surprised how closely an amp's response under identical conditions (the 9-11kHz sweep) matches that of the Helix...
As above, there are plenty of things about real amps I'm happy to have left out of a modeler, like tone controls that barely do anything when an amp is gained up high, the weight of my Marshall Major's transformers and cabinetry, standby switches that barely work...
"Noise curve" is Copyright Me, 2018. Just a way to describe the graphs in the OP, since they obviously don't just show aliasing (see above). If it did, then a real amp would show zero response apart from the original signal and the harmonics - would you like to place a bet on whether that's true or not?
(I wouldn't take the bet, 'cos I already know the answer and I'm cursed with a sense of ethics).
Oddly, the more accurate the modeller, the more noise you'd see - if every component in an amp is modelled perfectly, then the overall model will display just as much noise outside the original signal as the original amp did, and that wouldn't be aliasing.
Bet? I'm just tying to understand where the misunderstanding is, yours or mine. Ethics? Axe grind much? Pun intended..
Where did you get this zeal for "accuracy" and "perfection" in modeling? How granular is your definition of "accurate"? It would appear that it's a good deal more granular than mine.