Tarun, yes, we certainly do have to rely on our receivers for 7.1, since there is no 7.1 source material, but that's part of what we paid for when we bought the receiver. Processing such as DPLII and Logic 7 takes the anbience naturally present(in varying degrees)in two channel material, extracts it from the front channels, and steers it to the surround speakers where it belongs. The latest DPLIIx and Logic 7 can also extract some of the material in the side surrounds of 5.1(or the occasional 6.1)movies and steer it to the back surrounds to give a better surround effect.
So, a 7.1 setup can be useful with all source materials if there're at least a few feet behind the listening position so that a back surround effect can be realized.
