one system can described as linear system + non linearity. And a linear system cna be described using magnitude response and phase response as well as impulse response. The two are fundamentally the same thing just in different form. Unless you can hear over 100khz there is 0 chance of hearing the difference. From 44.1khz playback on the other hand there is very small but audible difference. Other than that it's only possible when digital filter changes the intermodulation distortion the dac produces.
And non linearity is simply all kinds of distortion and noises. And there are harmonic distortion and intermodulation distortion. And no matter what distortion it is, it's included in multitone measurements. And noises is simply measurable. When all of these are under 10ppm. It's simply ridiculous to argue that it's easily audible. It might be tiny bit of difference under most specific condition. But it's simple incredibly small.
And simply there isn't any measurements that isn't done yet. But I do agree some are hard to interpret. However we can surpass the human hearing without knowing the exact threshold of everything.
And non linearity is simply all kinds of distortion and noises. And there are harmonic distortion and intermodulation distortion. And no matter what distortion it is, it's included in multitone measurements. And noises is simply measurable. When all of these are under 10ppm. It's simply ridiculous to argue that it's easily audible. It might be tiny bit of difference under most specific condition. But it's simple incredibly small.
And simply there isn't any measurements that isn't done yet. But I do agree some are hard to interpret. However we can surpass the human hearing without knowing the exact threshold of everything.