 It is further argued that, because of technical progress in the science of sound transmission, equipment in the studio originating the programme should have a higher standard of performance than the equipment employed in reproducing it, since the former has a longer life.In fact, most professional audio production studios have several sets of monitors spanning the range of playback systems in the market.This may include a sampling of large, expensive speakers as may be used in movie theatres, hi-fi style speakers, car speakers, portable music systems, PC speakers and consumer-grade headphones.