CD media basics
introduction to CD-R and CD-RW
CD is the best sounding mass market audio medium ever. It will be replaced one day, but not soon.
CDs are cheap, light, robust, user-friendly, computer-friendly, mail-friendly and most music buyers have a player. Most recorded music is still sold on CDs—online and off by new distributors and old. People have more CD players than MP3 players, mobile phones or computers.
- Over 1 billion CD players sold to date (plus PCs and DVD players play CDs too)
- Over 2 billion mainstream CDs sell annually (over 5 million a day)
High street CD sales reached record levels in 2004/5 after a dip from 2000, but in 2007 they are clearly in decline. CD will probably be superseded by DVD and AAC or lossless compression at some point, but CD compatibility will live on in multi-layer DVDs well beyond that. Making records today still means making 16-bit 44.1kHz CDs, apart from the odd bit of vinyl. Downloads are generally compressed from CD masters.
iTunes sold over 10 billion tracks from April 2003 to 2010, the equivalent of a single year’s CD sales. The Majors’ total digital revenue including ringtones etc. is about 35% (2010).
Albums have been released on flash memory cards but that is still a novelty format for music releases. The limited edition Prince Opus iPod is a good example of premium-price alternative media.
You’ll probably make a CD-R master of your tracks, although DAT and analogue tape are also widely used.
Traditional CD standards include data, karaoke and multi-media, and new standards include DVD-V, DVD-A and Super Audio CD (SACD). This page deals mainly with the established CD-DA audio format.
There are three main types: standard manufactured CDs (CD-DA), CD-R recordable and CD-RW rewriteable.
- Standard manufactured CDs can be played on any CD digital audio player.
- CD-Rs can be played on CD-R machines and many but not all CD digital audio players.
- CD-RWs can only be played on CD-RW compatible machines.
Both writeable types can be burned to play in audio machines and PCs.
There are two main types of recordable CD, one for audio systems and one for computer systems:
Recordable audio CDs are intended to carry a record industry levy and are not interchangeable with computer CD-Rs. There is no levy in the UK.
- CD-R / CD-RW for CD digital audio (also called “for consumer” or “for music”).
- CD-R / CD-RW for CD (normally used in computer CD burners).
Recordings can be added to both CD-Rs and CD-RWs in a number of sessions before they’re finalised, but only CD-RWs can be re-recorded. Compatibility with other players is impaired if you write a track or file at a time rather than writing a whole disc at once. Recordable CDs can be played on CD writers before they’re finalised, but not on players. It’s worth knowing that blank media isn’t entirely blank and there’s always information on it that stops one kind being mistaken for another (whether you like it or not).
The best CD-R information resource I know online is Andy McFadden’s CD-R FAQ.
These five CD types are identified by logos on the media nd machines (although some computer players and burners only identify themselves in the manual).
|CD logo||Type of CD|
|normal pressed CDs (CD-DA)|
|consumer audio or music CD-R|
|consumer audio or music CD-RW|
|computer CD-R (audio, music and other files)|
|computer CD-RW (audio, music and other files)|
CDR/W burners used to be rated for up to three different speeds (e.g. 4x 8x 16x or 52/24/52):
- the slowest speed is for burning RW discs;
- the middle speed is for burning R discs;
- the fastest speed is for reading or digital transfer to computer.
However, today’s optical recorders burn may different kinds of media and the old 3-part speed description is no longer used. Now you will see something like this:
- Read Speed: 48x (CD) / 16x (DVD)
- Write Speed: 48x (CD) / 22x (DVD±R) / 8x (DVD±R DL)
- CD / DVD Rewrite Speed: 32x (CD) / 6x (DVD-RW) / 8x (DVD+RW) / 12x (DVD-RAM)
Recordable media is also rated to show compatible drive speeds. Fast media can normally be used on slower players and burners, but not always. Slow media will only work on drives that support a range of speeds and can detect the slower media. It’s best to use media rated in the same range as the drive speed. Audio burners and players (i.e. not computer drives) usually work in real time, although some dual drive duplicators go faster.
Make sure you keep your Operating System, burner software and firmware up to date. This Apple article has more information about media and drive compatibility.
DVD-R and DVD-RW speeds also appear on some burners. Here’s a comprehensive DVD FAQ by Jim Taylor.
For several years up to 2006 the Major record labels “copy-protected” certain CDs.
The original CD specification for discs and players didn’t include copy-protection. The only reliable copy protected discs are new types such as SACD or DVD-A which play on new machines.
Nevertheless big record labels have attempted to add copy-protection to CDs. The main copy-protection schemes used on CDs are:
- Macrovision (previously Midbar) Cactus Data Shield™ CDS300
- SunnComm MediaCloQ™ and MediaMax™
- First 4 Internet (F4i) XCP and XCP2
- Sony key2audio™ and key2audioXS™
Most recently (2006) EMI used CDS300 and Sony/BMG used MediaMax and XCP. Record labels pay a royalty of about 5¢ for each protected disc. UMG and WMG don’t currently use copy-protection on CDs.
2007: the Macrovision CDS300 and F4i XCP products have been removed from the web.
|This IFPI copy control logo means the “CD” is a non-standard disc and is not guaranteed to play in a standard CD, DVD player or PC.|
Protected discs are non-standard so there’s no guarantee they’ll play. They should not carry a Compact Disc logo. They can be copied using techniques such as:
- obscuring the outer track with felt tip pen (key2audio™);
- obscuring the outer session 2 track (XCP);
- holding the shift key while loading the disc (MediaMax™);
- using a Mac (CDS300, XCP, MediaMax™);
- using pro CD software (CDS300, XCP, MediaMax™, key2audio™);
- recording the analogue signal (any playable CD).
Over the past twenty years almost all the top selling music of the past fifty years has been released digitally on CD (far more than legally available online). Unless things change on the creative front that will remain the lion’s share of the industry’s music assets.
Everything that can be made can be copied (consider SDMI, DVDs, counterfeit money, credit cards and warez). Research in 2002 showed almost every copy protected CD track was already available online. It’s a kind of challenge—the massive libraries of bedroom MP3 downloaders are trophies, not really lost sales or music collections.
The Major labels have not been able to introduce reliable copy-protection, even with new media.
- The industry SDMI system for standard digital media security was cracked within days of release in 2000 and mothballed in 2001.
- Even DVD, designed to be secure, was compromised by the choice of CSS which was cheaper to build into players (and easily cracked).
- The multi-region DVD system, designed to protect vested interests, is now no more than an inconvenience for consumers.
- HD DVD and Blu-ray Disc copy protection AACS was broken within weeks.
Every consumer DRM product to date has been cracked. It’s hard to imagine a future with anything other than open, standard media.
Some CD copy-protection history:
- Autumn 2005: Sony/BMG USA and EMI Europe launched a new copy-protection campaign. Sony/BMG almost immediately withdrew XCP when they were sued for compromising users’ PCs. MediaMax was also questioned.
- Autumn 2004: Sony Japan announced it would stop using CD copy-protection.
- January 2004: Belgian consumer watchdog Test-Achats took the Majors to court over CD copy-protection (personal copies are legal in Belgium).
- October 2003: New legal SunnComm 3-copy limited CD “protection” can be defeated by holding the shift key when the CD is inserted. SunnComm threatened Princeton University for revealing this under the DMCA.
- July 2003: A consumer in France won the right to a refund for an EMI CD that wouldn’t play. The case was brought by consumer group UFC-Que Choisir.
- February 2002: Fahrenheit Entertainment settled over a SunnComm Charley Pride CD by implementing a returns policy.
- September 2001: Music City Records and SunnComm were found to breach fair-use (Audio Home Recording Act 1992).
The term unbranded is used for two completely different types of recordable CD:
- blank inkjet printable discs with a plain white or uniform finish from Sony, TDK, etc.;
- ordinary discs without a brand name whether plain, printable or otherwise.
Unbranded (no brand name) CD-Rs and CD-RWs can be anything from junk to top quality discs. There’s a lot of mythology about suppliers, countries of origin and dye colours, but unless you have some inside knowledge about the source it’s guesswork.
The term ‘Grade A Unbranded’ media doesn’t mean anything. These unbranded discs are by definition discs no one has put their name to. While that’s not necessarily a problem, the mystery is who then certifies them as Grade A (whatever that might mean). Manufacturing information about blank discs can normally be displayed using pro CD tools software.
To get a current recommendation for cheap, reliable CD-Rs check one of the popular online music or computing forums.
Red Book is the nickname for the 1980 international consumer audio CD standard and it means standard discs will play reliably on all players. You shouldn’t need to worry about what it says as long as you use standard CD media and recorders. If you want to go deeper on this you’ll find more information online (the two FAQ sites mentioned above are excellent).
Electronics companies and record labels would love to sell loads of new stuff and re-sell loads of old stuff, but the jury is still out on a possible replacement for CDs. The current contenders appear to be DVD-V (what we know as DVD), DVD-A and Sony/Philips SACD. This Surround Associates article describes DVD-A and SACD, but there is a debate about the real sound quality of these systems (this Elliott Sound Products article for example).
Here is a comparison of the key features:
|Audio capability||Can include
a CD layer?
The digital system in SACD doesn’t allow a technical comparison with 24-bit 96 kHz and there’s no consensus about its quality. In practice few albums were mastered in very high resolution audio so improvements in sound quality can be theoretical. Sony and Philips are building SACD into most of their new DVD-V players and many CDs, but if people won’t pay extra at some point the only advantage is copy-protection.
It’s not certain that CDs are ready to go the way of vinyl and cassette. There are still unanswered questions:
- what is the real trend from MP3 and the Internet?
- will people upgrade for better audio resolution?
- do people really want surround (5.1) audio for music?
- is surround relevant for stereo (car, PC, walkman, radio)?
- will the need for a video interface hold back DVD options?
- how will people use new portable media players and services?
DVD-V is a dark horse in the better stereo stakes, with the most players in homes and many DVD titles selling very well. DVD players can play CDs but there’s still confusion between the competing recordable DVD formats (DVD+R, DVD-R and DVD-RAM).
HD DVD has been beaten by Blu-ray Disc as a potential successor to DVD, but the demand will depend on HD content.
Universal Media Discs (UMD) might become popular for portable applications with the success of the Sony PSP (Playstation Portable). They are 60mm, 1.8 Gb optical discs, currently read-only, but proprietary Sony standards tend not to last.
Lossless CD-quality downloads are another contender for full-bandwidth audio.
It’s hard to predict what will happen, and without a compelling attraction most technologies fail. Microsoft’s HDCD (20-bit 44.1 kHz CD compatible format) hasn’t done too well so far. In the mean time multi-format discs with a CD layer are becoming the norm for spanning old and new standards.