Plugging in headphones, need setting change?

This is more of a curious / discussion type issue, rather than a help issue. Here's what I am wondering :

Let's say you have a pair of 5.1 speakers plugged into a 5.1 sound card, and you want to plug in stereo headphones in either a front audio "headphone" port or a headphone port on the actual speakers themselves. Do you need to change the settings the speaker settings under Advanced Audio options in Windows from 5.1 to stereo headphones? Would it matter which port you plugged them into with this?

I'm curious as well. I always change it to reflect when I have headphones plugged in but it is interesting. I don't notice any difference watching stereo video clips or listening to music I believe. Perhaps someone else can provide insight.