I have an HTPC mainly built for home theatre use.

I really like to clone my fronts to the rears to have that "immersed" sound feeling, and sometimes with a DSP effect added for some delay+reverb. Works nice with chillout and ambient, when you just want to relax while browsing the web.

Here is my problem, I dislike DolbyPIIx's 2ch -> Sorround, and DTS NEO 6's 2ch -> Surround conversions.

No matter on the settings they are still front channel biased.

My current setup is Soundstorm2 SPDIF -> Panny XR70 receiver -> PSB 7PT as fronts / Athena ASF2's as rears.

Only way to clone the rears is to use Dolby Digital, but that is a fairly lossy codec. Next best thing would be M-Audio 7.1 PCI cars with DTS output, but that is still lossy.

Having browsed around it seems that DVD-A's MLP codec (which is lossless) can do the trick, and my receiver can decode it. Any soundcards can output MLP?
Or are there any other options available to me, like 4ch PCM or similar?

Man this was so easy back in the day with analog outs lol.