The SACD format
What are SACDs?
Super Audio CD (SACD) were developed by Sony and Philips, the original creators of the CD. They look the same as ordinary CDs but, thanks to innovative recording and playback techniques, can deliver an amazing richness of sound and unprecedented levels of quality
What are the advantages of SACDs?
SACDs are recorded using a process known as Direct Stream Digital (DSD) that can capture a full range of sounds with incredible audio resolution, making it the closest approximation to the original analog waveform available.
DSD can even re-master old analogue master tapes revealing a new level of quality. SACDs are also capable of multi-channel audio containing up to 5.1 channels of surround sound.
What is multi-channel audio?
Multi-channel audio allows a more precise reproduction of the acoustic signature of the performance space by recording the sound from different positions within the space onto separate channels, which can then be recreated through an equal number of loudspeakers.
SACDs vs. CDs
How do SACDs compare to ordinary CDs?
SACDs have the same shape and dimensions as CDs. They differ in recording and playback methods, audio quality and storage capacity.
How are SACDs recorded?
CDs are recorded using Pulse Code Modulation (PCM), which allows for a sampling frequency of 44.1kHz encoded at 16-bit resolution. SACDs are recorded via Direct Stream Digital (DSD), which samples at 2.8224MHz encoded as single-bit data, making it 64 times faster.
How good is the audio quality of an SACD?
Playback on CDs has an upper frequency cut-off at just over 22kHz and a dynamic range limit of about 96dB. The cut-off for SACDs is beyond 100kHz and can deliver a dynamic range of over 120dB across the audible range.
The conventional PCM recording and playback process requires a variety of filters (decimation, interpolation, oversampling and low pass), whereas DSD is far simpler needing only a low pass filter for playback, giving a far more faithful reproduction of the original signal.
How much data can SACDs store?
Ordinary CDs can hold around 650–740MB of data. By contrast, a single-layer SACD can hold 4.7GB (over 6 times as much data), and a dual-layer disc can store 8.54GB.
A single-layer SACD can hold over 100 minutes of two-channel stereo audio (compared to 74 minutes on a CD) as well as multi-channel content.
Will ordinary CDs play on my SACD player?
Yes, a dedicated SACD player can handle all existing CDs.
Will SACDs play on my CD player?
There are three different types of SACD:
Single layer discs have one high-density layer.
Dual layer discs have two high-density layers.
Hybrid discs have one high-density layer plus one standard CD layer.
Hybrid discs are the only ones that will play on an ordinary CD player since they have a standard CD layer for compatibility.
What special feature does SACD support?
An extra data area has been reserved on SACD disc which will make it possible to include information (text, graphics and video).