Supposedly even with a 2.0 or 2.1 speaker setup, it can somehow give positional cues.
Probably not as well as with headphones, or with a 5.1 or 7.1 setup, but probably better than just a typical stereo output.
However, it might tweak the sound in such a way as one might just prefer a standard stereo output.
If you want to try it with a sound card, rather than do GPU --> HDMI ---> AVR, you could do the same thing as described above, except do it: Sound card -->optical out --> AVR, and that should provide you with the DSP processing from the sound card.
I have the Arx Ab1 speakers and the Ascend 170se speakers. For what it is worth, if I were to do a 2.0 setup, I would go with teh Arx Ab1. They have a bit better bass. If I were to do a 2.1 setup, it would be a tougher call.
The Arx Ab1 have a bit better clarity in dialog and are blacker/darker with it's sound. The Ascend 170se is more lively with its sound. It is hard to describe, but the best I can do is with music the Arx sound more like a studio recording and the Ascend sound more like a live recording. The Ascends are probably more of a natural and neutral sound, but the Arx sound is more clear and distinct. The ascends are more power sensitive and can get louder on less power than the Arx as well.
You cannot go wrong either way, they are both great speakers for $300-350 a pair. The differences I am describing are more subtle differences than they are drastic.
I hear the BIC F12 subwoofer is a nice $200 budget sub. You might want to look into that. I have not heard it myself, but I always see people talking about it. The Klipsch RD12 is always on sale at newegg for $280-300. That is also apparently a decent sub for the price (but its more of an HT sub than a music sub, as it is more rowdy than articulate, apparently).
Edited by Goride - 6/11/13 at 12:12pm