Also many encoders have things like a lowpass filter even on their higher presets - some people (often younger) may be able to hear those frequencies. It may b

Also many encoders have things like a lowpass filter even on their higher presets - some people (often younger) may be able to hear those frequencies. It may be that two different people have different results of being able to tell the difference due to physical differences, no matter the "effort" the put into listening, or training. But most of the time that's intentional, as high frequencies you "can't hear" just waste bits that could be used on something more useful, or even cause noise from aliasing and harmonics, as no actual playback equipment is perfect. And extending the frequency range makes it much harder to design the circuitry. All for something you can't hear :P It's another reason why high frequency (96khz) playback is kinda useless, or even make things worse, as the extra frequency range that gives cannot be heard by humans anyway, and just gives more opportunity for those higher frequency patterns to cause distortion. It may even be that people can "tell the difference" precisely because of those distortions. But that doesn't mean it's "better", indented, or even get the same result on different playback equipment.