The patents in question are for a speaker unit that boost sound output. THX was awarded a patent on the technology in 2008 and Apple is allegedly using it on the Apple iPhone, Apple iPad and other devices. THX is seeking money to compensate for missed royalties owed it, payment for damages and a sales ban on offending Apple devices. If the court were to find in favor of THX, in theory the Apple iPhone and Apple iPad could be banned from sales in the U.S.
Neither company would comment outside of THX which simply said that this was a "pending legal matter".