CD‑R may be the fastest growing mastering format, but its complicated subcodes and impenetrable protocols have made it anything but user‑friendly. As prices tumble and software evolves, however, it's an increasingly accessible medium. Mike Collins explains how he's mastered mastering on his Mac...
At last! The technology to master your own CD at home, and on a relatively affordable desktop system. That's what the latest generation of CD‑R recorders promises, though some credit should also go to a new generation of software packages.
One of the most popular CD‑R recorders is the Yamaha CDE100, which allows you to write discs at up to four times real‑time speed — typically about 20 minutes a disc. Prices on this model are coming down — it is now available for under £1500 including VAT. However, for many purposes, the new generation of lower‑cost CD‑R recorders (which offer twice real‑time recording speed) will easily suffice. Models such as the CDE102 from Yamaha or the CDR4220 from Plasmon are now selling for under £1000 including VAT, and are ideal for archiving your computer files to CD‑ROM.
A couple of things to watch out for when shopping around for a CD‑R recorder are whether it is compatible with the software you want to use, whether it supports Disk‑at‑Once mode properly, and whether it supports ISRCs and other codes you may need to input (if you're new to some of this terminology, check out the 'Bust That Jargon!' boxout elsewhere in this article). The new Sony Spressa 920 drive, for instance, like the Plasmon RF4100 drive, does not let you write ISRCs for each track, and some of the cheaper drives only allow you to create Track‑at Once discs, which cannot be used for making CD‑R masters.
Most CD‑R resellers are including software such as Astarte's Toast CD‑ROM Pro, or Incat Systems' Easy CD Pro within the price of a bundled package. Using these programs, you can create Macintosh HFS CD‑ROM discs, ISO 9660 discs for other computers, hybrid Mac/ISO discs, and various other types of CD‑ROM and audio discs. These audio discs are very basic, and can be useful as reference discs, but are not up to the standard of a CD‑R master (for sending to a pressing plant), as it is not possible to access PQ subcodes. Astarte do also offer the more advanced Toast CD‑DA software, however, which does give you access to subcodes.
However, if you have a Digidesign AudioMedia, Sound Tools, ProMaster 20, Pro Tools, Session 8, or Pro Tools III system, then you will almost certainly want to use Digidesign's MasterList CD 1.2 software, which not only gives you full access to all the subcodes and indexes, but also lets you set the gain of left and right channels independently, and gives you the option of using dither when burning your audio to disc. For this review, I decided to go with the Yamaha CDE100 and Digidesign's MasterList CD, although I also ran some tests using Astarte's Toast CD‑ROM Pro and Toast CD‑DA software for comparison (see the boxout on Toast elsewhere in this article).
The Masterplan
MasterList CD has recently been updated to version 1.2, and the latest firmware revision for the CDE100 is version 1.10. Earlier versions of MasterList CD and of the firmware in the CDE100 had problems related to the copy‑protect flags, which resulted in a click sometimes being heard at the end of the audio on the CD. Using MasterList CD version 1.2 with the CDE100 firmware version 1.10 sorts all these problems out. Also, support has now been added for seven new CD recorders, including the Kodak PCD225, Philips CDD522, JVC XRW2001, Pinnacle Micro RCD1000, Ricoh 1060C, Plasmon RF4100 and the Sony CDU920S.
MasterList CD lets you create both standard CD‑R discs and Exabyte DDP tape masters — with Grey Matter Response's Mezzo Master software and any Exabyte 8500 family 8mm tape drive. Exabyte offers several advantages over write‑once CD, especially if you already have an Exabyte drive for data backup or other purposes. For instance, Exabyte DDP tapes are written at two‑and‑a‑half times real‑time recording, with data error correction performed during writing. The 8mm tapes are also relatively inexpensive and can be written to more than once. Unfortunately, you cannot play these tapes back to hear the audio — the audio data is only accessible at pressing plants when the final CDs are made — so if you get two tapes confused, you might get a nasty surprise when your finished CDs return from the plant!
Using MasterList CD, your completed master tracks, whether sound files, regions or Sound Designer II playlists, are simply assembled to form the master list. The order and spacing of items in a master list are completely adjustable and non‑destructive. File support includes Sound Designer II and AIFF 16 and 24‑bit, mono and stereo files, as well as split‑stereo files from Pro Tools. Transitions between tracks can be seamlessly smooth, using editable, non‑destructive, RAM‑based crossfades. For easy level‑matching across the entire CD, the software provides location and level details of the audio peak within a selection, up to 100 auto‑locate points for auditioning between tracks, and independent channel level adjustment from ‑96dB to +12dB in 0.1dB steps. Unfortunately, you cannot display or edit the autolocate points, which I feel is a major omission from this software.
MasterList CD supports the full set of PQ subcodes, and for a simple project scenario, the essential PQ subcodes required are automatically constructed as the master list is assembled — so no further editing is needed before the disc is written. For more complex projects, MasterList CD allows creation of up to 99 tracks per CD, with up to 100 index points per track. Index points may be manually entered or set using Sound Designer II markers or playlist region boundaries. Conveniently, you can print track sheets with both master list and PQ subcode information, or create ASCII field‑delimited dumps for input to desktop publishing applications, databases and so forth. Another useful feature is that MasterList CD does not force you to go to Sound Designer II or Pro Tools to edit the start and end times of a file, region or playlist: these can be changed from within MasterList CD itself.
Once editing is complete, the entire master list is written to CD with just the click of a mouse, and the PQ subcodes are written simultaneously with the audio. Each master list can be fully auditioned using just about any Digidesign system to check track start positions, transitions and levels, and throughout the process you'll hear a true audio representation of your finished master — before writing the CD.
MasterList CD allows you to create an 'image file' before writing your CD. The idea here is that the image file contains an exact copy of all the data you want to write to the CD including all the audio, subcode data and any level changes or crossfades. This data should all be written contiguously (continuously, with no gaps between the files) to a defragmented hard disk partition for best results, and once this image file has been prepared, it can be written much faster to the CD.
Up To Speed
So how fast can you write a CD? Well, this depends on various factors. Firstly, how fast is your CD recorder? Some models can only write in real time — in other words, if the audio is one hour long, the disc will take one hour to write. This is called 1x speed in the jargon. You can get recorders which support 2x, 4x, and 6x speeds, but this does not mean that your system will allow MasterList CD to write at these faster speeds. Your system includes the particular computer you are using, such as a Quadra or a Power Mac, and these run at different speeds. The various Digidesign audio cards also run at different speeds. Your hard disk drive also has to be fast enough, and be able to suspend thermal recalibration while it writes to disc.
Some of the cheaper drives only allow you to create Track‑at Once discs, which cannot be used for making CD‑R masters.
In practice, the Pro Tools I, Sound Tools II, ProMaster 20 and Audiomedia II cards running on a Quadra 840 A/V computer provide the fastest speeds, and allow 4x writing of 16‑bit audio without creating an image file first. On the Pro Tools III and Session 8 systems, you will need to create an image file in order to write successfully at 4x speeds, and of the Macs, only the Quadra 840 A/V will achieve 4x speeds. All other Macintosh models will only manage 2x speed, achieved mostly using image files. This is because the Pro Tools III system is based on the Session 8 card, which was a lower‑specification card intended to sell at a lower price than the Pro Tools I 8‑track systems. The reason that you can get the highest speeds on a Quadra 840 A/V rather than on one of the more recent Power Macs is that the speed of the the NuBus and that of the CPU when running 680x0 code on this model outstrips that of any other Macintosh. Power Macs have to emulate in software the instructions to the 680x0 chip (the one used in all Macs prior to the Power Mac range), as Power Macs use the newer, Power PC CPU chips.
Dithering About
One of the options in MasterList CD's Preferences dialogue box (using Dither) needs some explanation. Dither is a special form of randomised noise, used to mask quantisation noise in digital audio systems. Digital audio's poorest distortion performance occurs at the lowest end of the dynamic range, where quantisation errors can occur — leading to distortion of the signal. If you introduce very low‑level random noise, known as dither, this can reduce these quantisation errors to improve the subjective performance of your 16 bits.
Quantisation from 24‑ or 20‑bit down to 16‑bit resolution also results in a loss of sound quality, and an increase in low‑level noise and distortion. The TDM processing in Pro Tools uses 24 bits, so this has to be pulled back down to 16 bits by rounding or truncation, prior to mastering for CD. The resulting rounding error can produce audible distortion at low levels, and if the audio signal is repeatedly processed and pared back to 16 bits, the losses accumulate. So, once you have finalised your processing and mixing, you need to prepare a final output file which uses just the 16 bits which are available on DAT or CD, rather than the 24 bits available within your TDM system. The TDM buss works at 24‑bit resolution, to provide the extra dynamic range you need to mix several 16‑bit signals together, and you will also need extra dynamic range if you process 16‑bit audio using any digital effects such as compressors, EQ and so forth.
Proper use of dithering techniques can convert the low‑level non‑linear distortion into a simple steady hiss, at the expense of increased background noise. The perceived level of this can be greatly reduced by optimising the shaping of the overall noise to match the ear's frequency‑dependent sensitivity curves — a process known as 'noise shaping'. Both the Waves plug‑ins and Apogee's MasterTools plug‑ins which are available for Pro Tools TDM systems offer alternatives to the simple dithering algorithm available in Pro Tools. If you have not applied any dither or other form of noise‑shaping using Pro Tools, Waves or MasterTools, then you can select the Use Dither option in the Preferences dialogue, which instructs MasterList CD to use its own dithering algorithm to reduce the sample size of a sound file (eg. from 24 to 16 bits), or for noise‑shaping of requantisation noise in a 16‑bit file.
Talking about plug‑ins, there are several of these available for both Sound Designer II and for Pro Tools TDM systems, which are very useful when preparing audio prior to CD mastering. Apogee's UV22 encoding in their MasterTools plug‑in will appeal to some, while others may prefer Waves IDR noise‑shaping. Crystal River offer their ProTron, while QSound have the Q/Sys Expander — both of which allow you to alter the stereo 'picture' of your audio. Lexicon's NuVerb also has various processing algorithms and sophisticated reverb patches, which can enhance your mixes considerably. Both Waves and Antares (formerly Jupiter) Systems offer de‑essing, compression and expansion plug‑ins, and Waves offer sophisticated equalization plug‑ins.
Pulling A Chain
So, you can make one‑off discs quite efficiently using the MasterList CD/Yamaha CDE100 system. But what about short runs? The Yamaha CDE100 does not support daisy‑chaining. However, if you have a CD recorder which does, such as the Sony CDW900E, MasterList CD lets you enable up to 16 chained recorders, so that you can make your own 'short runs'. Alternatively, you can use Toast with the Kodak Disc Transporter, rather than resorting to a pressing plant — which typically offer minimum runs of 500 discs.
With the Kodak PCD Write 200 and 600, or with the Philips CDD 521, you can use the Kodak Disc Transporter system to produce batch runs of up to 75 discs. This process does take several hours with the PCD 200 or the CDD 521, which run at 1x or 2x speeds, but is considerably faster using the PCD 600, which supports 6x speed.
Summary
To sum up, MasterList CD will unquestionably be of great interest to project studios — many of whom are likely to have (or be thinking of buying) a Pro Tools system with a CD‑R machine for backup and archiving. Mastering to Exabyte is a viable alternative to CD‑R, and Pro Tools/ Macintosh users may already have an Exabyte drive to use for backups of Pro Tools files using Grey Matter Response Mezzo software, or for backup of general computer files using Retrospect backup software.
If you are serious about mastering CDs which you intend to have replicated, then the Sony CDW900E is actually a better choice than the Yamaha CDE100, although, unfortunately, this model is no longer in production. The Yamaha CDE100 is certainly one of the best alternatives, as it supports just about all the features required, and is readily available to buy. If speed is important, then the Yamaha is the best choice — as long as you are using a Quadra 840 A/V Mac and a Digidesign system other than Pro Tools III/Session 8. Of course, Apple no longer manufacture the Quadra 840 A/V, and if you have just bought a Pro Tools system, it will be Pro Tools III!
Nevertheless, MasterList CD is the best software choice for Digidesign users who wish to make CD masters, although Astarte's Toast CD‑DA does provide a viable alternative if you simply want to produce reference CDs, or if you want to produce short runs using the Kodak Disc Transporter.
Don't Forget The Falcon!
There are a number of devotees who have been attracted by the advanced features available at an affordable price on the C‑Lab Falcon. The good news for Falcon users is that a software package, CD‑Recorder v1.0, is now available which will work with the Yamaha CDE100 and CDE102. This is ideal for data backup, and can be used to create basic audio CDs for use as reference discs. CD‑Recorder v1.0 is available separately or bundled with the CDE102. Distribution is by Digital Media — contact John Sharp on 01422 340875 (fax 0181 656 2442) for more details.
Bust That Jargon!
This article is, unfortunately, full of jargon — it goes with the territory. I had to go through something of a learning curve to get up to speed with all the terminology related to CD mastering, so I'm now in a position where I can demystify some of it for you!
- BY THE BOOK — BUT WHICH?
The Sony/Philips standard for CD‑DA (Digital Audio) discs is known as the 'Red Book', and Red Book CDs are what we all know as the audio CDs we buy in the record shops. The standard for recordable CD‑R discs is known as the 'Orange Book', which defines the format of a write‑once CD, not only for audio but also for computer data. The Orange Book effectively defines a superset of the Red Book specifications, so Red Book‑compatible CDs can be created on a write‑once disc.
Disk‑at‑Once mode is where you write the whole disc in one pass, while Track‑at‑Once mode lets you write one or more tracks, put the disc to one side for some time, then write some more tracks until the disc is filled up. Most newer CD‑R drives, including the CDE100, support Disk‑at‑Once recording, to let you create 'Red Book' standard discs, and you can supply these to a mastering facility to press discs in volume from. In Disc‑at‑Once mode, the writing laser is never turned off during the write process, and the disc is written from beginning to end without stopping: first the table of contents, then the lead‑in, followed by the audio data and the lead‑out. In Track‑at‑Once mode, the laser in the CD‑R recorder always stops writing between each track, before and after the the lead‑in, and before writing the lead‑out. If you try to produce a CD‑DA disc in this mode, various errors will show up when it is tested at the CD mastering facility — and the disc will most likely be rejected.
The important thing to remember here is that some CD recorders can only write using Track‑At‑Once mode to create 'Orange Book' standard discs — and discs written in this way cannot be played until the final recording has been made to the disc. In a variation of Track‑at‑Once mode, so‑called 'multi‑session' CDs can be written to at different times — which is useful if you want to just use part of the CD at first, and add more data later as it becomes available. Multi‑session discs also conform to the 'Orange Book' standard, and can be played back with any number of completed sessions written to the disc, unlike the Track‑At‑Once discs.
- SUBCODES & MARKERS
All audio CDs have eight channels of subcode data interleaved with the digital audio data — the P, Q, R, S, T, U, V and W channels. With normal audio CDs, only channels P and Q are actually used by the CD player, while channels R to W are used to store video information on CD + G discs, and MIDI information on CD + MIDI discs. The P channel information tells the CD player when tracks are playing and when they are not, while the Q channel describes track and disc running times, copy protection and emphasis information, disc catalogue barcode, ISRC codes and so forth. The barcode and ISRC codes information is normally supplied by the record company.
ISRC's are International Standard Recording Codes, which are code numbers used to uniquely identify audio recordings. The publishers and record companies can use these numbers to refer to their records of who did what on the recording — to identify all those who should share in the royalty income from the recordings, including producers, engineers, artists, musicians, composers, and so forth. The use of ISRCs is not mandatory for Red Book Audio discs, as it is with Mini‑Disc for instance, but increasingly, the major labels such as Sony are including ISRCs — which has got to be good news for the creators of the recordings.
The copy‑prohibit 'flag' prevents any digital recorder from recording that track. This is not the same as the more recently‑developed SCMS (Serial Copy Management System) code, which allows data to be copied once, but prevents second‑generation copying of the material to another digital recorder. SCMS prevents you making a a copy of a copy digitally (although you can always make an analogue copy!). However, the Yamaha CE100 does not let you write SCMS flags, so you will need to use a Sony CDW900E if you need this feature.
The Emphasis 'flag' tells the CD player to use its analogue de‑emphasis circuit. This is the circuitry built into every CD player after the D/A convertor, which corrects the high‑frequency emphasis boost applied before recording in some earlier, low‑cost CD player/recorders such as the popular Casio models. It is quite easy to forget about this, and digitise audio which includes an emphasis boost. You can easily tell that the track has a high‑frequency boost when you compare it with the original, and usually the effect will not be very pleasing.
- INDEXES & ACCESS POINTS
You can have up to 99 tracks on a CD, and each track can have up to 100 markers, or Index Points within that track, numbered from 0 to 99. All tracks have an index 1, which should represent the start of the audio material in that track. If a track has a gap containing silence before it (after the previous track ends), then index 0 represents the start of that silence gap. When a CD player skips to a specific track, it locates to the index 1. When a CD player is told to jump directly to a particular track, it mutes its audio outputs, then searches across the CD to find the start of the audio in the track you want — which is the track's Begin Access Point (at the index 1). When it finds the right point, it unmutes its audio outputs and starts playing.
Because a CD player takes a small (but significant) amount of time to unmute its audio outputs, you can set a track's Begin Access Point slightly earlier, typically a little way into the silence gap before that track's audio, to make sure that the CD player's audio outputs will be completely unmuted by the time the audio starts. A similar situation exists at the end of a track: If a CD player is put into Random Play mode or told to skip to a track, when it reaches the end of the track it is playing, it will mute its audio outputs and jump to the next track to play.
The place at the end of the track where the CD player will stop playing before jumping to another track is called the track's End Access Point — which is actually the next track's Index 0 point (or the Index 1 point, if no Index 0 exists). To make sure the CD player completely finishes playing the audio before jumping to another track, the End Access Point should be set a little way after the end of the actual audio. CD recorders that only support Track‑at‑Once mode do not support Begin and End Access offsets, so if you are using one of these recorders, you will have to insert a little silence at the beginning and end of your audio tracks manually, using Sound Designer II or Pro Tools.
Mongrels & Cross‑Breeds
There are several other types of CD‑ROM disc which you can write using software like Toast CD‑ROM Pro.
The Macintosh HFS format is used to create CD‑ROM discs which will 'mount' on the desktop of any Macintosh computer, so that you can then use these as read‑only storage discs — typically to archive your general computer data.
The ISO 9660 format is used for CD‑ROMs that are intended for DOS, Windows, and other ISO file systems. These can also be read by Macintosh computers, but will have ISO 9660 or DOS format file names.
The Mac/ISO hybrid format allows you to create CD‑ROMs that can be read on both Macintosh and ISO file systems — with data common to both file systems shared on the CD‑ROM.
Mixed Mode CD‑ROMs have the computer data as track 1, with the audio tracks following, although you are advised not to play the computer track back on an audio CD player, as this can lead to speaker damage.
Labelled With Love
What about labelling your discs? Up until now, there were only two ways to mark or label these: you could write on them with a felt‑tip pen, or you could buy an expensive (£5,000 and up) bubble jet printer, and print directly onto the disc. There are two obvious problems with the pen: the disc doesn't look professional, and the ink comes off in the CD player, which can end up damaging the drive. The printer looks better, but it is far more expensive than the recorder itself.
There is now a third, simple and inexpensive method of labelling CDs, however. With the Neato labelling system from Rocky Mountain Traders, if you can print with a laser or inkjet printer, you can custom‑design, print and apply centred circular labels to CDs without the risk of damaging either the disc or the player. The Neato labelling kit contains the two‑piece Neato applicator, one hundred 113 mm circular blank labels, and both Mac and PC templates for FileMaker Pro, Aldus PageMaker, Quark Xpress and CorelDraw.
Rocky Mountain Traders can also supply extra blank labels in assorted matt and gloss colours, as well as printable clear polyester. The NEATO labeller uses a cylindrical basepiece, which allows you to place the circular self‑adhesive labels onto CDs without leaving bubbles. You use the supplied templates to create the artwork on your computer, and then simply print it onto the blank label.
The kits cost under £100 including VAT, and can be obtained from Stan Grossman at Rocky Mountain Traders (freephone 0500 026103, or fax 0171 209 0645).
Just A Little Bit Of... Toast
Astarte's Toast CD‑DA is very straightforward to use. You open a new file, add the tracks you want on your CD, and set the track spacing, Catalogue Code number, ISRC codes, Emphasis flags, and Digital Copy Prohibit flags. You can use either AIFF or SDII files, and even import regions from SDII files if you like.
Once you have your list of files, you can audition these using the transport controls, and change the running order by simply dragging the files up or down in the list. Before burning a disc, you can use the Check Speed feature to quickly test the transfer rate from your hard disk, or if you want to be really sure the disc will write OK, use the Simulation Mode, which runs through a full‑blown simulation of the whole procedure (and, of course, takes as long as writing a real disc!).
I also have a copy of Astarte's Toast CD‑ROM Pro, which I use for archiving my Macintosh files to CD‑R. This has an excellent feature which you can use to create a temporary hard disk partition of exactly the right size to match the capacity of your blank CD‑R discs. I used this to create a temporary hard disk partition of 650Mb on my Micropolis 2217 1.7Gb A/V drive, copied my audio files onto this, and made sure that I defragmented this hard disk 'volume' using Norton Speed Disk every time I edited or replaced a file — to make sure that all these files were located contiguously on the hard disk. This way, I was able to use the 4x writing speed with the Yamaha CDE100 with no problems.
The CDs I burnt using Toast worked perfectly in my Denon CD player, and it was somewhat faster to use than MasterList CD, although I particularly missed the ability to set the gain of the left and right channels. This meant that to get all the levels correct, I had to go back and edit the original Sound Designer II files individually, after auditioning the list in Toast CD‑DA first, and making notes about roughly how much to change the levels. So, if you want to make quick reference discs to give yourself some idea of how your tracks will sound playing back off CD through your hi‑fi, I would call Toast CD‑DA a viable alternative to MasterList CD.
However, if you have a Digidesign audio card, and really intend to have discs pressed from your CD‑R master, or want to make sure all your levels, timings and subcodes are correct, then MasterList CD is the only sensible choice.
Further Information & Pricing
Both the Yamaha CDE100 and CDE102 are distributed in the UK by five different companies at present. All five sell the writers as part of bundles containing the software and hardware required to run the drives and burn CDs. For Mac use, most offer the Yamaha units in conjunction with Astarte's Toast software (in either CD‑ROM Pro or CD‑DA versions), among other options — but only the Tyrell Corporation, amongst the Yamaha CD distributors mentioned here, sells Digidesign's MasterList CD. Some of the companies sell other CD‑R writers too, such as the Philips CDD521, or the Sony CDW900E and CDU920S. Just to further confuse matters, the five Yamaha distributors also sell systems on to retailers such as TSC in London (tel: 0171 258 3454), who then resell to the public. Because each distributor and reseller has its own pricing structures, and offers different permutations of bundled software and hardware, it's not possible to go into pricing details for each one, for reasons of space, but here, at least, are the contact details for each distributor.
- CD REVOLUTION
- KOCMEDIA
- RAM PERIPHERALS
- TRACKS DATA
- THE TYRELL CORPORATION