The routing (currently) is supposed to be as follows: FxBus 0/1: Stereo L/R Fxbus 2/3: Front L/R FxBus 4/5: Rear L/R FxBus 6/7: Center/LFE FxBus 8/9: Side L/R (with 8 PS enabled) There is an issue with the routing of stereo only audio in Vista/7 which results in the audio no longer getting routed to FxBus 0/1 and instead gets routed to FxBus 2/3 or 4/5 or 6/7 (people seem to get different results and I do not know if the results are consistent). Some people set AC3/SPDIF as the default device as a workaround, but I do not know if doing so effects any other channels, nor if there are any other issues that might result from doing this (I use WinXP, which does not have this issue). Due to the above, there is no way to differentiate between audio that is supposed to be stereo only, and audio that is supposed to be directional audio (for whichever channel/bus that stereo audio ends up getting routed to for you (i.e. in your case, stereo vs front)). This means that you would need to use separate configs (one for stereo only audio, and another for multichannel audio). As for your side channels, I am not sure why it is being routed to FxBus 2/3... Maybe try enabling kX's 8 point surround manually: Also, there may be additional issues related to x64 versions of kX that have not been reported as of yet (or I am just not aware of), etc.