It’s not difficult to understand why Jamie Foxx is especially drawn to roles that involve music.  After all, he studied music in college, and he’s got a successful side career as an R&B singer.  (His single “Blame It” is currently #1 on four of Billboard’s singles charts.)  In “The Soloist,” which opens Friday, he plays a homeless cello prodigy named Nathaniel Ayers.  His friendship with Los Angeles Times columnist Steve Lopez (Robert Downey Jr.) brings media attention to his plight, and Ayers’ challenging journey is chronicled in the film. Foxx talks about how he was able to get into the mindset of a cellist and, specifically, Ayers.. (CLICK ON THE MEDIA BAR BELOW TO HEAR JAMIE FOXX)