A Guide to SACD

[Big Daddy]

For additional information, check my threads on DVD-A and DualDisc and Home Theater Audio CODECs.

A GUIDE TO SUPER AUDIO CD (SACD)

Prepared by Big Daddy

What is SACD?
SACD is not a home theater audio CODEC. It is a high resolution format developed by Sony/Philips in 1999 as a replacement for music CD’s.

Is the Sound Quality of SACD Better than CD?
Yes, SACD uses a high resolution format. It has better sampling frequency, better frequency response, and better dynamic range than standard CD. In addition, many SACD titles, but not all, are multi-channel.

How Can I Tell If a Disc Is SACD?
All SACD players and discs have the following logo on them:

SACDLogo.jpg

What Is a Hybrid SACD?
A Hybrid SACD contains two separate layers. One layer carries the SACD information (a stereo or multi-channel mix) and the other layer carries the normal CD information. Only hybrid SACDs can be played in a standard CD player. Non-hybrid SACDs must be played in a SACD player or a compatible DVD player.

What Is DSD?
SACD audio is stored in a format called Direct Stream Digital (DSD), which differs from the PCM format used by CDs.

DSD is 1-bit and has a sampling rate of 2.8224MHz. This gives the format a greater dynamic range and wider frequency response than the CD. Sony and Philips claim that the system is capable of delivering a dynamic range of 120dB from 20Hz to 20kHz and an extended frequency response up to 100kHz, although most currently available players list an upper limit of 80–90kHz.

What Is the Difference Between SACD and DVD-Audio?
SACD uses optical discs and DSD encoding. To listen to SACD content, you need a SACD Player or a SACD-compatible DVD player. You can play the Hybrid SACD (not the standard SACD) in your CD (home or car) and standard DVD player. However, you will only hear the stereo CD content.

DVD-A uses the DVD media and PCM encoding. To listen to DVD-A content, you need a DVD-A compatible DVD player. If you use a standard DVD player, you will only hear the stereo content or Dolby/DTS Digital content, depending on the encoding. You cannot play a DVD-A disc in your home or car CD/SACD player.

Comparison of DSD and PCM
Converting from analog sound to PCM and back to analog sound involves a number of processing steps. Each step causes distortions such as quantization noise (please refer to footnote 1). The noise may result in further deterioration of sound quality and needs to be filtered out. DSD, however, is a very simple way of converting analog signal to digital with a smaller probability of sound deterioration.

Because of the nature of converters used in PCM and DSD, one cannot make a direct comparison between the two formats. An approximation would place DSD in some aspects comparable to a PCM format that has a bit depth of 20 bits and a sampling frequency of 192kHz. PCM sampled at 24 bits provides theoretically an additional 24dB of dynamic range. Due to the effects of quantization noise, the usable bandwidth of the SACD format is approximately 100kHz, which is similar to 192kHz PCM.

For a discussion and debate over DSD versus PCM, read the following:
http://en.wikipedia.org/wiki/Direct_Stream_Digital
http://stereophile.com/thefiftheleme...th/index3.html
http://www.hydrogenaudio.org/forums/...9&#entry427509
PCM v DSD Comparison: 16/44.1, 24/96, 24/192, 64x DSD, 128x DSD

What Type of Cables Do You Need for SACD?
SACD players are not permitted to digitally output encrypted DSD signals. Therefore, you cannot use Toslink (Optical) or Digital Caoxial S/PDIF (Sony/Philips Digital Information Format) cables. Initially, players supported only multi-channel analog output (please refer to footnote 2). Later, some proprietary digital interfaces such as Denon Link or I-Link (IEEE 1394, Firewire) permitted encrypted transmission of DSD. HDMI (version 1.2 or above) can also be used for transmission of DSD signals. The HDMI version number does not refer to the cable. It refers to the transmission and receiver chips in the player and the receiver.

Should We Set the SACD Player to PCM or DSD?
The biggest headache in digital audio is converting analog to digital and then converting it back to analog again by using D/A chips. Converting DSD to analog is surprisingly very simple. Unfortunately, converting PCM stream to analog is a lot more difficult. In that respect, DSD has an advantage and it makes sense to let the receiver/processor receive the DSD signal and convert it to analog without any processing. At the same time, DSD does not allow the receiver to perform any type of processing such as bass management and DSP (PLIIx, etc) without FIRST converting it to PCM.

If you are using HDMI connection for multi-channel SACD, you basically have two options:

1. Set the player to DSD and send the SACD signals to the receiver/processor with HDMI 1.2 or higher and let the receiver/processor convert the signal to analog without any processing. The results are generally excellent and make most people happy. Unfortunatly, you won’t be able to perform bass management and this puts people with small/bookshelf speakers at a big disadvantage. Moreover, you will not be hearing bass the most optimum way as the subwoofer only receives the signals that the sound engineer put there. There will be no redirected bass from the front or surround speakers. Remember that the position of the source of the low frequency waves in a small home theater room is an important factor in receiving good bass.
2. Set the player to PCM and send the PCM streams to the receiver/processor with HDMI 1.1 or higher and let the processor perform all sorts of DSP processing and bass management. Will the signal be degraded? Probably yes. Can we hear the difference? Probably no, although you may hear significantly better bass output in your room. Is the quality still better than CD? Probably yes.

List of Receivers/Processors That Can Handle DSD

http://www.avsforum.com/avs-vb/showp...81&postcount=1

Can I copy a SACD?
SACDs are copy protected and cannot legally be copied. Besides, no SACD recordable discs and no SACD recordable drives are available. However, the CD layer of a hybrid SACD can be copied if it is not copy protected.

How to make a DSD Disc
This guide is intended for users of the Korg MR-1/MR-1000 portable audio recorders that record in 1-bit DSD format.

http://www.ps3sacd.com/dsddiscguide.html

FAQ About PS3's SACD Capability
Sony’s PlayStation 3 (20GB, 60GB, and the old 80GB models) can play music in SACD format through an HDMI cable. However, they do not output DSD over the cable, but instead convert it to PCM. The 40GB PS3 and the new 80GB PS3 models do not play SACD music.

http://www.ps3sacd.com/faq.html

Importance of Calibration
Many SACD and DVD-A titles are available in 5.1 multi-channel sound format. In order to enjoy the music in the most optimum way, you need to calibrate your audio system and adjust your speakers/subwoofer. Although many new receivers have their own built-in calibration programs, I highly recommend the use of an SPL meter in addition to them. Radio Shack offers two excellent choices below $50. I also encourage you to read Calibrating Your Audio with an SPL Meter. Pay close attention to the section at the end on subwoofer positioning and its interaction with the main speakers.

Where Can I Buy SACD Music?
There are approximately 5,000 SACD releases since the introduction of the format, mostly, but not exclusively, in Jazz and Classical music. You can check the following sites for SACD releases:

http://www.sa-cd.net/titles
http://www.sonybmgstore.com/search/sacd.htm
http://www.amazon.com/exec/obidos/se...rocess=default
http://www.arkivmusic.com/classical/...&album_group=4
http://www.telarc.com/sacd/all.asp?m...17JFHC9&q=cbsa
http://www.chesky.com/core/productli...ctcategoryid=3
http://www.musicdirect.com/category/2
http://www.cduniverse.com/browsecat....cart=693240373
http://www.cdpacific.com/search.asp?...wsacd=1&swlp=0
http://store.acousticsounds.com/sacd...FQgmawodPSZbDA
http://www.jr.com/JRSectionView.proc...=610000#Format
http://search.ebay.com/sacd_W0QQcrlp...Z1205296851390

SACD, DVD-A, and DualDisc Reviews
http://www.audaud.com/index.php
http://www.highfidelityreview.com/index.asp

Popular SACD Players
http://www.oppodigital.com/
http://www.sonystyle.com/webapp/wcs/...tegoryId=27883
http://usa.denon.com/ProductDetails/...ndChangers.asp
http://us.marantz.com/Products/349.asp
http://www.pioneerelectronics.com/PU...liteDVDPlayers
http://www.onkyousa.com/prod_class.cfm?class=DVD
http://www.tacp.toshiba.com/dvd/prod...?model=sd-6980
http://www.teac.com/esoteric/Audio_Players_CD_SACD.html
http://www.arcam.co.uk/prod_diva_DV135_intro.cfm
http://www.arcam.co.uk/prod_diva_DV137_intro.cfm

MORE INFORMATION & REFERENCES

http://en.wikipedia.org/wiki/Sacd
http://www.sonymusic.com/sacd/faq/index.html
http://www.sa-cd.net/faq
http://www.merging.com/uploads/asset..._pdfs/dsd1.pdf
http://www.merging.com/uploads/asset...on%20Guide.pdf

FOOTNOTES

1. Quantization is the process of approximating a continuous range of values by a relatively-small set of discrete symbols or integer values (approximating analog signals with discrete digital values.) Quantization Noise is introduced by quantization in the analog-to-digital conversion process.
2. When a SACD player is connected to a receiver with multi-channel analog cables, the player must perform digital to analog decoding and send the analog signal to the receiver. In this case, calibration and bass management adjustments such as speaker sizes and channel levels should be done in the player's setup menus or the receiver must have bass management for the 5.1 ANALOG inputs. If the player lacks calibration adjustments or the receiver cannot perform adjustments for analog inputs, bass management cannot be performed.