Big Speaker Sound Without The Big Speaker Whether you’re looking for your first home theater sub/sat system or want to upgrade to more performance, you’re in for a big surprise in a small, compact package from Polk Audio. The predecessor to Blackstone TL, our RM series, was always about “Big Speaker Sound Without The Big Speaker.” Blackstone TL represents a significant leap forward, delivering an astonishing home theater performance never before heard in compact loudspeakers.Time Lens Technology-The acoustic centers of the tweeter and mid-bass driver are located in the same plane for superior imaging