aircraft carriers and other high noise environments. In 1963, EV received an Academy Award for their 642 Cardiline shotgun microphone, the first ever given for an audio product. Electro-Voice launched its RE Series of microphones in the 1960s, notably the RE15, which was used extensively by musicians on television shows. The RE series used "Variable D" technology first developed by EV in 1953, which eliminated changes in tone and frequency response corresponding to changes in the physical distance of the sound source from the microphone. The RE20 broadcast microphone was introduced in 1968, followed by the RE27N/D in the late 1980s, using neodymium magnets. Both continue to be used in recording studios and on the concert stage. In the early 1970s, EV developed the first commercial system for matrix four channel stereo called Stereo-4. When Columbia/CBS and Sony developed their Stereo Quadraphonic system (SQ) that system became the leading matrix system. Electro-Voice then adapted their decoders so they also could play SQ records as well as Sansui's QS records. The EV system could also simulate four channel sound from two channel sources. In 1978, Electro-Voice patented its Constant Directivity Horn, which produced an even balance of frequencies across the listening field. It overcame the uneven dispersion of high frequencies that affected the typical high frequency horns used in many professional sound speakers until the late seventies. Also in the 1970s, EV acquired TAPCO. The company, founded by Greg Mackie, specialized in audio mixers. TAPCO products soon became prominent in the EV product line. In the late 1980s, EV became the first microphone manufacturer to use neodymium magnets in its microphones. The N/DYM microphones were introduced in the mid 1980s to combine the high output and high frequency response characteristics of condenser microphones with the rugged shock resistance of dynamic microphones. Around the same time EV's first wireless microphones were being produced. Mergers The company merged with Telex Communications in 1998. Prior to the merger, EV was owned by Mark IV Industries, Inc. through its subsidiary, Gulton Industries, Inc., and had manufacturing plants in Buchanan, Michigan; Newport, Tennessee; Sevierville, Tennessee; and Gananoque, Ontario. Electro-Voice's headquarters were in Buchanan, Michigan until the merger with Telex Communications. In June 2006, EV, along with all of Telex Communications, became part of Bosch Security Systems division. Today EV manufactures widely used broadcast microphones as well as loudspeakers and various other professional audio equipment. Superfund site