Beginner's Guide To New High-Resolution Audio Formats

CD revolutionalised the way we buy and play music. When CD was launched in the early 1980s, we were given a way to hear new music with less of the fuss involved with playing LP records. The new Compact Disc was smaller and easier to carry, slightly less scratch-prone, and could play through for almost an hour and a quarter without having to lift a finger.While most people, hi-fi buffs included, embraced the format, for many audiophiles and music fans the quality never really met, let alone exceeded, that available from a good record player. At its launch, CD was described by co-inventor Philips as ‘Perfect Sound Forever’, a description that has come back to haunt the industry. Over the following years, the technical argument that ‘a bit is a bit’ and therefore CD cannot be wrong has been truly demolished. The truth is, we know a lot more about digital audio now than we did in 1982, including all the problems that contributed to the clinical, thin sound that began to be associated with the CD format.

A new beginning...
With the introduction of DVD video in the late 1990s, a way to improve the CD was seen. The greatly increased data capacity of DVD could be used, not to store space-hungry video, but instead very high quaity music, using all the extra space to encode audio with much more precision. Instead of using 16-bit encoding, you could use up to 24-bits, greatly increasing the loudest possible captured sound, while still ensuring that the very quietest parts (where all the crucial details are!) remains preserved. Bandwidth could increase too, that is the range of frequencies that could be recorded, from the lowest to the very highest notes. Traditional audio theory expected sounds only up to 20kHz to be reproduced, as humans were believed to be unable to notice sound any higher in pitch. While the case for ultrasonic perception in humans remains controversial, what cannot be ignored is the principle that extending the upper limit allows the highest frequencies that we definitely can hear, to be captured far more accurately. With less distortion appearing at this upper threshold of audibility, the sound may be heard as much smoother, and more natural.

The solutions
Most electronics companies were backing a proposed DVD-Audio format, which would provide not just higher quality sound on the same size disc as a CD, but would do so in up to 5.1 channel surround-sound. This suround-sound, or multichannel, aspect of the format was probably insisted upon as a means to add value for the mass consumer. For a new format to become successful, it must be embraced not just by the quality-minded enthusiast but by all consumers. Since most CD buyers are quite happy with the sound of their stereo CDs, it would have been futile to try to sell the new DVD-A discs solely on the strength of better sound quality.

Meanwhile, Sony and Philips, inventors of the CD, announced their own version of a high-quality CD replacement. Rather than unite the industry by adding their combined authority to the fledgling DVD-A format, Sony and Philips, perhaps fearing the drying up of income from their 20 year patent on CD technology, created their own higher-quality CD replacement, which they called SACD — the Super Audio Compact Disc. This used a wholly new digital encoding system (for DVD-A was just an extension of the PCM system still used today on all music CDs). Sony’s DSD (Direct Stream Digital) technology was the basis for the SACD, a system that gives sound quality a little below DVD-A at its best setting quality, but still better than familiar CD.
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