Pioneer uses MK decoding chips. Founded in 1973, M&K has always been a pioneer in the field of sound. It invented the world's first active subwoofer. Its Realtime recording studio released the first CD in the United States in 1982, leading the industry into CD digital. era. M&K was also the first company in the world to participate in THX certification, becoming the first speaker manufacturer to pass THX certification at that time. At present, more than 350 professional units around the world have designated M&K speakers and subwoofers.