Long story short it really depends on the type of speakers you are attempting to drive, their efficiency, and your headphone out power capacity. As others have mentioned "most likely" un-amplified, the speakers won't produce to their capacity. The "best" alternative would be to power them via an audio receiver, which you could acquire fairly cheap at a pawn shop that accepts some form of stereo input, the easiest would be to send audio to the receiver via a 3.5mm to RCA cable from you computer to the receiver. Then you would simply have to plug the speakers into the receiver, and adjust the volume to your liking. The added bonus here would be you could tweak the sound to your liking via the receiver bass and treble knobs.