|Are you sure the laptop only supports 4.0/4.1? That's a strange configuration that iirc was only used back in the late 90's by cards like the SoundBlaster Live. Most laptops today only offer stereo output (some support 5.1 through S/PDIF, but you'll an external decoder, such as an AV receiver, to use it). |
But if your laptop actually has 4 channel output, then just continue what you're currently doing--have the media player or AC3/DTS codec downmix the 5.1 to stereo.
Socket 939 | Dual-core Opteron 185 @ 3.2GHz | 4GB | 1.0TB | Win7 x64
GeForce GTX 460 1GB | X-Fi Ti Pro | A8N32-SLI Deluxe | Antec P182