[yzhou]

There's a big difference in impulse response with different sample rates, any one can see it on a oscilloscope, I bet some one can hear the difference.

Those who don't have a oscilloscope can see the picture here: http://i.imgur.com/wY0wzcW.png

[nullc]

What you are showing is _precisely_ the effect of low-passing, nothing more, nothing less.

See the digital media primer 2 for more information on that: https://wiki.xiph.org/Videos/Digital_Show_and_Tell

If humans were able to hear audio above 22kHz (or what not) in any meaningful way, we'd expect to be be able to demonstrate that effect in carefully controlled studied and then that lack of low-passing may matter; but that isn't what the best evidence so far shows.

[yzhou]

The low-passing with a brick wall filter on 44.1KHz audio can be a bad thing sometimes, for example, pre-echo https://en.wikipedia.org/wiki/Pre-echo You won't hear the pre-echo on a 2.8MHz DSD audio.

[yzhou]

In the real world, it is almost impossible to make a voltage divider with 24bit resolution. So all the DAC makers have to convert 24bit audio into lower bits(6bits to 1bits), this step requires oversampling the original audio. It is a lot easier to oversample a 192KHz/24bit audio than a 44.1K/24bit audio, and the ringing is much less after oversampling the 192KHz/24bit audio.

[fancyketchup]

The two pictures don't have the same vertical scaling, and it's clear that the probe is ahead of the LPF in the signal chain.

[yzhou]

the probe is placed on the headphone jack. The difference in the vertical scaling is that 0dB DSD signal is 6dB below a 0dB PCM.

[yzhou]

The brick wall filters used on low sample rate sound cause ringing in the time domain, which can "blur" the neighboring impulse.