RECORDING YOUR OWN CD-R's
RECORDING YOUR OWN CD-R's
by Bruce Bartlett
Right on your own desktop, you can make a compact disc by using a CD-R recorder. The disc will play in a CD-ROM drive or audio CD player. It's exciting to hear one of these CDs playing your music with the purity of digital sound.
CD-R stands for Compact Disc Recordable. This optical medium is a write-once (non-erasable) format. Sound quality meets or exceeds compact disc standards, and the expected lifetime is about 70 years.
Erasable CDs are called CD-RW (re-writable). CD-RW discs cost more than CD-R discs, but CD-RW discs can be used over and over. Currently, a CD-RW disc will play only on a CD-RW recorder, not on a standard CD player (but this may change).
How can you use the CD-R format? Well, you could make demos that sound much cleaner than cassettes. Or make a one-off copy of your stereo mixes for clients. Use the CD-R as a premaster to send to a CD replicator. Another function is to compile sound libraries of production music, samples, and sound effects. The CD format is a more dependable storage medium than DAT, so it's a great way to archive your recordings.
Want to try CD-R? First you have two basic choices of CD-R recorder:
- A standalone CD-R recorder, sometimes called a consumer CD recorder.
- A computer peripheral CD-R recorder, also called a CD-R drive. You plug it into your computer system.
Both types produce discs that sound equally good.
The standalone CD recorder has everything you need in one chassis. Inside is a CD transport, laser, and microprocessor. On the back are analog and digital ins and outs. On the front are the level meters, record-level knob, display and keypad. Because the standalone unit needs no external computer, it's user-friendly. Just connect your audio source containing an edited program, either on DAT or analog tape. Set the recording level and start recording.
In contrast, with a computer CD-R drive you need to copy your edited DAT program to your hard drive, then copy the hard-drive recording to CD-R. This takes longer, but the computer CD-R recorder costs less than the standalone recorder.
Here are the features of both types of CD burner: Standalone CD recorder:
- Costs about $600 and up.
- Does not require a computer.
- Writes audio but not data.
- Most use "Consumer Audio" blank discs costing about $3-5.
- Makes CD-R and CD-RW discs (if CD-RW is included).
- Records at realtime speed.
Computer CD recorder:
- Costs about $200 and up.
- Requires a computer, at least 16 MB RAM, sound card (16-bit/44.1K), CD-R software, and a 1 GB or bigger hard drive with 680 KB/sec minimum throughput.
- Requires a fairly fast computer: Pentium 100 or faster, Mac Centris, Quadra or Power Mac with 8 MB of RAM.
- Plugs into an IDE or EIDE ribbon cable or SCSI card. EIDE works as well as SCSI if you don't run other programs in the background.
- Writes audio and/or data.
- Uses 74-minute (750 MB) CD blanks costing about $1-2 each.
- Makes CD-R and CD-RW discs (if CD-RW is included).
- Records 2X to 6X normal speed. Best choice for multiple copies.
- Can be internal or external.
If you want to burn more than one CD at a time, you can daisy-chain CD-R recorders together, or use a tower CD-R duplicator.
While conventional CD players follow the Sony-Philips Red Book standard, CD-R conforms to the Orange Book part II standard. Once recorded, a CD-R disc meets the Red Book standard.
A recordable CD is the same size as a standard compact disc, but is more colorful. On top is a layer of gold; on the bottom is a recording layer made of blue cyanine dye. Actually, the blue layer appears green because of the gold layer behind it. Some CD-R discs use a yellow (gold) dye of phthalocyanine.
Yellow dye lasts a little longer in accelerated aging tests, and it may work better with high speed CD-R drives. Still, most CD-R writers are optimized for cyanine dye, which can handle a wider range of laser power and wavelength.
A blank CD-R is made of four layers:
- Clear plastic layer for the label (protects the gold layer)
- Gold (reflects laser light)
- Dye (for the recording)
- Clear plastic (protects the dye layer).
The dye fills a spiral groove which is etched in the bottom clear-plastic layer. This groove guides the laser.
To record data on disc, the laser melts holes in the dye layer. The plastic layer flows into the holes to form pits. During playback, the same laser reads the disc at lower power. At each pit, laser light reflects off the gold layer. The reflected light enters the laser reader, which detects the varying reflectance as the pits go by.
In contrast with a standard CD, a CD-R disc has two more data areas:
- The Program Calibration Area (PCA). The CD recorder uses this area to make a test recording, which determines the right amount of laser power to burn the disc (4 to 8 milliwatts).
- The Program Memory Area (PMA). This area stores a temporary table of contents (TOC) as the CD-R tracks are being assembled. The TOC is a list of the tracks, their start times, and the total program time. The recorder uses the Program Memory Area for this information until it writes the final TOC.
Before we look at the differences among CD-R recorders, we need to understand the concept of a "session." A session on disc is a lead-in, program area, and lead-out. Each session has its own TOC. Each lead-in and lead-out consume 13.5 MB of disc space.
With the "Multisession" feature, you can write several sessions on a disc at different times. This feature comes in handy when you need to add information to a disc a little at a time. Only the first session on disc will play on an audio CD player, so the discs are just for your own use -- not for distribution.
Some CD-R recorders permit "Disc-at-Once" recording, in which the entire disc must be recorded nonstop. You can't add new material once you write to the disc. With the right software, Disc-at-Once lets you set the length of silences between tracks (down to 0 seconds), and lets you control how the tracks are laid out on disc. Disc-at-Once is the pro audio format.
Most CD-R recorders allow "Track-at-Once" recording. They can record one track (or a few tracks) at a time -- up to 99 tracks. You can play a partly recorded disc on a CD-R recorder. But the disc will not play on a regular CD player until the final TOC is written. Track-at-Once is not recommended for audio because it puts 2-second spaces and clicks between audio tracks.
If you want no pauses between tracks (as on a live album), get a CD-R recorder with Disc-at-Once, and some software that can adjust the pause length down to zero. Note that a standalone CD-R recorder will copy your edited program as it is, with or without pauses.
Other things to look for: a buffer of at least 1 MB and high-speed CD-RW formatting (5 minutes or less). Be sure that you can return the CD-R writer if it proves to be unreliable.
BLUE DYE vs. GOLD DYE
As we said, a blank CD-R disc contains a layer of dye in a preformed spiral groove. The laser burns pits in the dye. Two types of dye are in use: blue or gold. The blue dye, which appears green because of the gold backing, is Cyanine. The gold dye is Phthalocyanine.
What are the differences? Mitsui claims that gold dye is more durable and reliable than blue dye when exposed to heat, humidity, and light. "Unlike a Cyanine based CD-R, which shows degeneration from continuous exposure to light and heat under Carbon Arc Lamp testing, Mitsui's Phthalocyanine based CD-R remains durable and remarkably stable throughout the entire test exposure time of 180 hours.
"Mitsui CD-Rs' projected longetivity was tested by employing the Orange Book Standard for Block Error Rate (BLER) set by the industry for CD-Recordable media. The Phthalocyanine-based Mitsui CD-R was subjected to 80 degrees Celsius and 85% RH for over 1000 continuous hours, the equivalent of more than 100 years under normal use. The Mitsui CD-R was consistently able to retain data and outperform the Orange Book Standard."
According to Dana Paker in the Incat Systems Web pages, "Cyanine dye is the de facto standard; the Orange Book was written based on the original cyanine dye discs from Taiyo Yuden. Most CD-Recorders are optimized for cyanine dye. Cyanine discs are compatible with a wider range of laser powers.
- Phthalocyanine dye has performed better than cyanine dye in accelerated age testing, and may work better in higher speed recording (which requires higher laser powers.)
- However, all of these differences aside, it appears that in most cases, the two types of discs perform in essentially the same ways -- it's at the extremes and in the worst-case scenarios where these differences appear most marked.
When you prepare an audio program for transfer to a computer CD-R drive, you first have to dump the audio to hard disk. Audio consumes a lot of space. A 74-minute audio program fills 750 MB. So a hard drive of at least 1 GB is recommended, with a throughput of at least 1000 KB/sec. The audio data should be on its own separate drive or logical drive. You could divide the 1 GB drive into two logical drives: Drive C could be 200 MB for programs, and Drive D could be 800 MB for audio. Most hard drives do a thermal recalibration every so often. This pauses the hard-disk operation up to 1.5 seconds, which causes errors in CD writing. You want a hard drive that postpones thermal recalibration when the disk is in use. This type is called an A/V (audio video) drive.
CD-R EDITING SOFTWARE
The computer CD-R drive requires a CD recording program, usually packaged with the recorder. You don't have to use that program; other ones are available that you might prefer. Be sure the program is compatible with your recorder. Most software requires at least a Pentium 100 computer with 16 MB RAM.
There are many CD-R recording programs, but only a few are meant for audio. Most audio CD-R software allows Disc-at-Once recording and PQ encoding. Disc-at-Once lets you set the length of pauses between tracks, or eliminate them. PQ encoding is the timing info for tracks on an audio CD. To control the length of pauses between songs on the CD, you need a CD-R recorder with Disc-at-Once in its firmware, and software that allows Disc-at-Once writing. The Track-at-Once feature is undesirable: it always puts a 2-second gap and a click between songs. The click is caused by a .wav editor which adds ASCII data to the end of the .wav file. Usually this data is the name of the editor software and the creation date. To prevent this, go to the Options menu in the .wav editor and turn off that function.
Be sure that your CD-R software lets you control the length of silent spaces between songs, down to 0 seconds (for crossfades between songs, or for live recordings without a silence between songs.) Also make sure that the software will work with your model of CD-R recorder.
HOW TO USE A STANDALONE CD-R RECORDER
Let's say that you've compiled a DAT of song mixes. You want to copy them onto a CD by using a self-contained CD-R writer. The first step is to edit your mixes into a finished program. To do this you'll need a sound card and a 2-track digital editing program. Here are the steps:
- Connect your DAT recorder to the sound card. Transfer your mixes from DAT to hard disk.
- While viewing the soundfile waveform, mark each song as a region (a selected segment of audio). Using a mouse, fine-tune the start and stop points of each region so that there are no noises between songs.
- Assemble the songs in order into an Edit Decision List (a playlist or cue sheet). The total playing time should be under 74 minutes to fit on the CD-R disc.
- Between songs, put silent spaces or crossfades. Three to four seconds of space is typical.
- Have the computer change the level of songs that need it.
- Start recording on your DAT. Play the cue list off the hard drive and copy it to DAT.
- Once your edited program is on DAT, write a start ID 1/2 second before each song. Renumber the program numbers.
Now you're ready to play the edited DAT into the CD-R recorder. Connect the DAT's output to the CD-R recorder's input. Set the level and begin recording. Your program will copy to disc in realtime.
Depending on the CD-R recorder, the DAT start IDs may or may not convert to CD track numbers. If not, you can use a converter box, or add the track numbers manually while you record.
Here is a typical procedure for burning a CD with a standalone CD-R recorder:
- Select whether you want to increment tracks manually or automatically.
- Select whether you want the recorder to go into record mode automatically when the first Start ID comes in (assuming a digital source).
- Insert a blank CD. The recorder will calibrate for the optimum recording power.
- Select analog or digital source.
- Press RECORD to go to record-standby mode. If your source is analog, adjust the recording level. Make sure that your presets and connections are correct; you are about to record the disc! It is a write-once operation.
- Press PLAY to begin recording, and start your source. Or if automatic recording is on, just start the source. The CD-R recorder will begin recording when it sees the first Start ID.
- Increment the tracks manually if you set the CD recorder for that mode.
- When done, press STOP to end the recording.
At this point, you can record more tracks if you wish. Each track can be from an analog or digital source.
When the recording is complete or the disk is full, press FINALIZE and RECORD. In two minutes, the unit records the final table of contents and the disc leadout.
There is your finished CD. It really is that easy.
HOW TO USE A CD-R DRIVE
The procedure for this type of CD-R is different. First make the right connections. If your hard drive and CD-R drive are IDE or EIDE, plug the CD-R drive into the IDE/EIDE ribbon cable. If your CD-R drive is SCSI, plug it into your SCSI adapter card and terminate the SCSI port on the CD-R drive.
You also need to make audio connections. If your mixes are on DAT, plug the DAT's digital output into your sound card's digital input. If your sound card has no digital input, plug your DAT's analog output to your sound card's analog input. Other sources can be analog tape, LPs or cassettes. Just connect the analog source signal to the sound card's analog input.
You'll need two types of software: audio-editing software and CD-R recording software. The first type records .wav soundfiles on your hard disk, and lets you edit them. The second is used to select and sequence the .wav files, and to transfer them to CD. Some software can do both functions.
Let's say you've recorded a number of song mixes on tape, and you want to transfer them to a CD-R. Depending on your software, you can prepare your audio program in one of three ways:
- Option 1. Record each mix to hard disk as a separate .wav file. Use your software to trim the start and stop points of each .wav file (remove noises and silence before and after each song). You might want to defragment the hard disk after recording the .wav files so that the disk can be read faster. Arrange the .wav files in order in a playlist.
- Option 2. Start with a tape of unedited song mixes. Copy all the mixes to hard disk as one long .wav file. Then have the program break it into separate .wav files, one per song. Launch the CD-R software. Arrange the .wav files in order in a playlist.
- Option 3. Start with a tape of unedited song mixes. Copy all the mixes to hard disk as one long .wav file. Using a digital audio editing program, edit the program to adjust the silent gaps between songs. In the edited program, note the start time of each song. Write down these times. You will use them to create a playlist.
Save the edited program as a new soundfile on disk, or copy the edited program from hard disk to DAT. If you did the latter, copy that edited DAT program back onto hard disk as one soundfile.
Launch the CD-R software. Then create a playlist that notes the start time of each song within the edited soundfile. Actually, rewrite each start time about 1/4 second before the song starts, so that the CD player will play your CD-R without missing the beginning of each track. You are creating markers or pointers to define track IDs. Your finished CD should have the same silent gaps between songs that are in your edited program.
The total playing time of the playlist must be less than the CD-R maximum length of 74 minutes.
BURNING THE CD
Now that your program is in final form, it's time to write the CD. If necessary, blow dust off the laser lens. Turn on your CD recorder and make sure your computer has recognized it. Insert a blank disc.
Any data interruption during CD writing can cause errors. So before you record, turn off any TSR programs, screen savers, networks, alarms, reminders, anti-virus programs, and incoming faxes. In a Windows computer, select Control Panel/System/Device Manager/CD-ROM. Select your CD-R device, click on the Settings tab, and turn off "Auto Insert Notification."
At this point, you are almost ready to burn a CD-R. If you select "On-the-Fly" mode, the computer will read your soundfiles from random locations on your hard disk and will put them in order as the CD-R does a burn. Caution: this process has a relatively slow data transfer rate if your computer or hard drive are slow. This slow throughput might cause "buffer underruns" which create disc errors. However, you can prevent this problem by telling the CD-R software to write a "Disk Image" file first. An image file is a single file containing a copy of all your sound files, in the order you specified in your playlist. You'll need up to 750 MB of FREE disk space for the image file. The computer will copy the image from hard disk to CD-R during a burn. As the image is written, the recorder light might flash, but the laser is running at low power to avoid burning pits.
If your CD recording software reads one continous soundfile from your hard drive and writes it to CD using pointers for start IDs, you probably don't need to make an image file. Just write the CD-R.
Creating a CD on the fly (without an image file) takes no extra disk space, but it requires a fast Pentium to prevent errors with high disc speeds.
Most CD-R drives can burn discs at 1 or 16 times normal speed, and read discs at 6X to 24X normal speed. High speeds do not degrade sound quality. Contrary to intuition, high-speed CD-R writers create discs with fewer errors. How can this be? At high speeds, the laser burns for a shorter time and so has less time to drift. Also, the rapid high-power heating of each pit creates sharper pits, which are more readable. A writing speed of 2X is said to be the most reliable.
When you're ready, begin the transfer to the CD-R disc. The CD recorder will burn the tracks according to your playlist, with the specified track numbers, song order, and spaces between songs. You can check how the transfer is going by looking at the display on your monitor screen. As soon as the recording is done, the display will indicate that the TOC is being written. Finally the CD-R drive will eject the disc when it is done.
Now you have a finished CD. To prevent error-causing fingerprints, be sure to handle the disc only by the edges. Pop the disc in an audio CD player, press Play, and check that all the tracks play correctly. Do not expose the disc to prolonged sunlight. You can burn more discs of the same program, or start over with a new one.
CD-R LABEL EDITORS AND APPLICATORS
Once your CD is written, label it on the gold side with a water-based pen such as a Sharpie. Or you might want to label the CD with a neat, disk-like label of your own design. You need some blank CD labels, a label applicator, and label-design software. Some software can also print liner notes, including the track numbers, titles, and timing.
Some engineers prefer to label the CD-R blank before they burn the CD. An off-center label can unbalance the disc and cause data errors, so it's better to know that before burning than after.
Here are some makers of CD labeling products:
- Neato Media Labeling Products, 888-575-3873, 203-466-5170, http://www.neato.com.
- PressIt CD Labeler Kit by Rocky Mountain Traders, phone 914-359-0689 or 406-549-4445, www.mvd.com/pressit.
- The Label Applicator by Pro Source Sales & Marketing (no software), phone 800-903-1234.
- Great Gizmos Stick-it Right CD labeler kit.
- Avery 5824 Laser CD-R Disc Labels.
- Memorex CD Labeling Kit
- CD LabelCorp offers blank labels and an applicator.
- Rimage Corp. makes the Perfect Image CD Printer, a standalone printer that prints directly on the CD disc. $3995, 612-944-8144 or 800-445-8288.
- Fargo Electronics makes the Signature CD Color Printer, also a standalone printer that prints directly on the CD disc. $1295, distributed by Microboards Technology, 612-470-1848, www.microboards.com. It must use specially coated CD-Rs.
BLANK CD-R DISCS
These are made by TDK, Verbatim, Kodak, Taiyo Yuden, 3M, Sony, Maxell, Memorex, Mitsui, and others.
BOOKS ABOUT RECORDABLE CD
"The Complete Recordable-CD Guide" by Lee Purcell and David Martin, SYBEX, Inc., 800-227-2346. "Recordable CD Bible" by Mark L. Chambers, IDG Books Worldwide, Inc., 415-655-3200.
WEB SITES ABOUT RECORDABLE CD
www.osta.org, www.cdpage.com, http://ghost.rssi.ru/public/hardware/cdrw/faq.htm, www.cdarchive.com/info
Copyrighted 1999 by Deltamedia. May not be reproduced in whole or part without permission.