Im glad you've touched on this. Ive been developing a theory that the computer OS, and the daw having to conform to it, degrades audio by adding unecessary processing.
My thinking about this started in '07, when the modest mackie HDR standalone recorder jusy seemed to have a solidity to the sound vs dp. Ditto for the d8b digital mixer and dsp vs the motu and pluggins. Even summing digitally sending tracks from dp to the mackie (spdif) vs rendering inside the daw had a similar effect of solidity. Ive even noticed that ipad based recordings, and portable handleld recorders, seem to offer that solidity to the sound. Like more dense, fuller, dimensional. You can hear this on youtube demos of the avid eleven rack vs the avid eleven pluggin, which have the same sounds built in.
I almost commented this when i first heard your demo, but i was hestiant to sidetrack the convo.
If you think about it the mpcx uses computer type hardware components so its not digital hardware thats the issue, my theory is based on the OS, which is bare bones and custom for standalone devices. Perhaps better clocking? Maybe its the connection protocal to the computer, the USB, TB, ect. Thats also absent in the standalones.
It could be interesting, if the mpcx and mpc software i have, have any of the exact same samples, to render them on the mpcx and the computer, and see if they null, and sound the same.
I couldnt help but think about how much more advanced the mpcx is vs the old cassette based portastudios.