jbl synthesis scl 4xlJBL Synthesis SCL 4XL In wall speaker for home theater with high capacity and wide coverage JBL Synthesis SCL 4XL is an in wall speaker developed for home theaters where you want a solution that can deliver consistent sound to multiple seating rows. It works as an LCR behind an acoustically transparent screen or as a surround channel in larger rooms. With a compression driver, HDI horn, and dual 8 woofers, you get a speaker that delivers both control