The concerts began with U2's remix of M's "Pop Muzik" played through the PA system. The killer taunts her over the PA system. This would include turntables, speakers, and a PA system. These violins may need to be hooked up to an instrument amplifier or PA system. Feedback that occurs from a vocal mic into a PA system is almost always avoided. This control equipment is also used to separate zones in a PA system. The Bob Welch and Steve Miller sets were marred by PA system problems. PA system woofers typically have high efficiency and high power handling capacity. Another use of two-way radio technology is for a wireless PA system. Schaeffer used a PA system, several turntables, and mixers. The PA interview can be considered of great significance to an organization's PA system. The band rented David Lee Roth's PA system for their shows.