Hi folks - I recently bought some Altech Lansing USB speakers to use with my MacBook. They work just fine, however when they are not plugged in, my MacBook now can't find the internal speakers. In the Sound Preferences panel, the only option when the speakers aren't plugged in is "Digital Out - "Built-In Output". Also, the digital out port is constantly glowing red. Has anyone else had this problem...and is there a fix? Thanks in advance for any help!