1. I have read that upsampling using SRC at 24/96 and foobar sounds better than 16/44.1, so is there any software that upsamples to 24/192 and would that be even better.
2. Is the limitation USB, since I think digital can output 24/192khz and or since coax/spdif directly into a DAC/receiver sounds worse than USB which can only do 24/96? Would firewire solve this problem
3. Why does upsampling work at all? Since original redbook is only 16/44/1 why would anything higher unless originally higher rates like SACD etc be better.
You might want to read the various white papers Dan Lavry has written concerning sampling, oversampling, jitter and other digital subjects. Very educational. Check out the support area of http://www.lavryengineering.com.