If I buy a soundbar that is a 2.1 is there any downside of supplying it with a 3.5mm auxiliary audio in vs over HDMI? I ask because I bought a Epson 2250 and want to connect it to a soundbar, preferably a Klipsch cinema 400, and want to make sure that the limited connection options on both devices wont have a negative effect. it claims "5.1 decoding for virtualized surround sound" but not sure how that is transferred over this type of cable.
No, the cable is a simple analog line with two wires and a ground, one is L one is R audio.
Not that "virtual surround sound" that is it's own thing, that just uses slight delay and other tricks to do positional audio. That you can do with any stereo setup, but for a real 5.1 signal, you need a 5.1 capable cable and other hardware to work with the signal.