JBL MTS12 Loudspeaker System12 Full Range Loudspeaker System MTS12 is a professional grade 12 (304. 8 mm) two way speaker system designed for karaoke rooms. The two way speaker combines a custom made 12 woofer with a patent JBL 2414H C compression driver, and stands itself out for high power handling, large dynamic, warm vocal ranges and extended low bands. Its 70 100 coverage pattern provides smooth and even coverage whether installed in vertical or horizontal orientation.