Fucked up sound, only when playing DVDs

[FS]

For as long as I can remember on this PC (which is a few months old), when I play DVD movies, the sound is slightly garbled and fuzzy all the time. This is the only time when the sound is fucked up - not when I play a sound file from my hard drive, or a movie from my hard drive, or an audio CD in the DVD drive. Next to the DVD-ROM drive on my PC, there's also a DVD writer drive. Playing a DVD on that one has the same effect.

Could this just be to blame on two shitty DVD drives which are most likely of the same brand, or might it be a software issue I could solve by downloading something?