[Zarotu]

I figured out that the reason for my low quality music was due to plugging into the headphone jack in front of my case. I now have the headphones plugged in the back, but I want both headphones and speakers connected to the back. Currently I have the speaker's plug next to the headphone jack for easy access when I feel like switching.
How do I plug both headphones and speakers to the back? and How do I easily switch between headphones and speakers with that setup?

 

[jiiteepee]

Is there just onboard sound chip or some sound card in use? With onboard chip you could try by connecting Headphones into Front L/R and Speakers into Rear L/R (or vice versa). Setting the speaker mode to 4 channels (mixer panel) allows stereo signal through both channels. Control the output either through mixer software and/or volume control found from speakers (many playback software lets you select output channels freely from available ones).

 

[kabraxcis]

You could also just buy a switch, although I doubt you'd want to plop down extra cash when you can just do it manually every so often.
 
Really depends on the frequency of which you swap the two, and how lazy you are to do that.