on mac you can use soundflower to route audio inside the pc.spire wrote:why would you sample from spotify? why not just download a high quality wav? put them on an ipod and then plug the ipod into the mpc somehow?
but as far as the way you're asking, i don't think it's possible to route the audio of specific program to certain outs unless your soundcard's drivers/software have that capability. i have a steinberg ur28m which comes with an app called dspMixFX which allows you to route different mixes to different outputs. maybe your soundcard has something similar?
for windows there seems to be something similar called jack, never tried it tho...
http://www.grame.fr/~letz/jackdmp.html