|
Earthworks (corporation)
David E. Blackmer (January 11, 1927 – March 21, 2002) was an American audio electronics engineer, most famous as the inventor of the DBX (noise reduction), DBX noise reduction system and founder of dbx (company), dbx. As well as audio noise reduction, Blackmer worked on extending the frequency response of audio electronics beyond the conventionally accepted audible range of 20 kHz. He also published research on the value of ultrasonic frequencies in sound reproduction, claiming that the time resolution of human hearing is 5 microseconds or better—which would correspond to a frequency of 200 kHz, requiring audio equipment ideally to have a flat response to that frequency. Blackmer attended High Mowing School in Wilton, New Hampshire. He started in audio at Lafayette Radio in Boston in the 1940s and studied electronics in the United States Navy, U.S. Navy and at Harvard University and Massachusetts Institute of Technology, MIT. He later worked at Trans-Radio Recording ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DBX (noise Reduction)
dbx is a family of noise reduction systems developed by the company of the same name. The most common implementations are dbx Type I and dbx Type II for analog tape recording and, less commonly, vinyl LPs. A separate implementation, known as dbx-TV, is part of the MTS system used to provide stereo sound to North American and certain other TV systems. The company, dbx, Inc., was also involved with Dynamic Noise Reduction (DNR) systems. History The original dbx Type I and Type II systems were based on so-called "linear decibel companding" - compressing the signal on recording and expanding it on playback. It was invented by David E. Blackmer of dbx, Inc. in 1971. A miniature dbx Type II decoder on an integrated circuit was created in 1982 for use in portable and car audio, although only a few devices took advantage of it, such as certain Panasonic portable cassette players and Sanyo car stereos. dbx marketed the PPA-1 Silencer, a decoder that could be used with non-dbx play ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
