Now I think the fact that you're recording orchestral samples instead of live sources might be the reason why you are saying the sound card doesn't matter. Going back to my photography example, instead of taking pictures of life shots (with in theory unlimited resolution), you are photographing an animation cell. This has a limited resolution (compared to a real-life 'image'), so you don't need as good quality lens/capture system. If you're only recording samples/keyboard sounds, the extra "resolution" (or detail) provided by a Pro soundcard might be wasted. Hope this makes sense!