cond0lence Posted August 27, 2007 Share Posted August 27, 2007 http://spectrum.ieee.org/print/5429Maybe the best article I ever read over the 2 Sides of the Music Industryand that every advantage try to hide a bigger disadvantage.When the compact disc (CD) was introduced in the early 1980s, there was much for audiophiles to be happy about. Digital audio removed many of the physical restrictions vinyl had imposed, such as concerns about surface noise (caused by dust, scratches, the lacquer itself, and so on) and limited dynamic range. The CD was capable of supporting a dynamic range of about 96 dB. For most of the 1980s, when CDs were still high-end products and mastering engineers largely did not have access to digital signal-processing technologies, albums released on CD tended to make use of this better dynamic range.Unlike vinyl, which had varying loudness limits due to its physical characteristics, the CD had a definitive peak loudness limit due to its specified digitizing standard, a form of pulse code modulation (PCM). PCM had previously been used in telephony as a method of digitizing an analog signal. When an analog signal is sampled for digitization, each level of the signal is quantized (stored as a number in binary). How frequently samples of the signal are taken is specified by the sampling rate, and the total number of unique quantization levels capable of being stored is determined by the number of bits. When Sony and Philips specified the standard for CD audio, they determined that the sampling rate would be 44.1 kHz with 16 bits per sample. Using the rule of thumb, the approximation of 6.02 dB of dynamic range per bit gave CD audio roughly 96 dB of dynamic range. The highest loudness level (16 bits of all 1's) was designated as 0 decibels full scale (dBFS). Lower levels were assigned negative numbers.In the 1980s, CDs were mastered so that songs generally peaked at about -6 dBFS with their root mean square (RMS) Link to comment Share on other sites More sharing options...
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