Logitech V20 Stutter

Ever since I updated to the latest OSX, my Logitech V20 Notebook speakers have been stuttering while playing DVDs or MP3s. This only happens when I'm using products such as DVD Player or iTunes, and does not happen when the speakers are unplugged. It also happens when I'm watching a video with sound on YouTube. The stutter affects video as well, causing it to freeze, skip, and then resume playing.
Here are the speakers: http://www.logitech.com/index.cfm/speakersaudio/home_pcspeakers/devices/199&cl=us,en
Any ideas?