CD Duplication – How It Works

By December 9, 2017Uncategorized

What is CD Duplication?

CD Duplication is the process of producing a copy of a CD master disc by "burning" audio or data information onto a blank CD Recordable disc (CD-R) using a laser. Although digital audio formats have become increasingly popular over the last decade the CD still holds more than half of the market share with regards to the number of audio albums sold.

The burning process is carried out using an optical drive. Optical drives can be found in almost all laptops and desktop PCs. The drive consists of a tray in which the disc is placed; in the case of a laptop optical drive, the laser that burns information onto the disc is integrated into the tray and can be seen when the drive tray is ejected. In PC based optical drives, which tend to be larger units, the tray simply holds the disc in place and the laser is contained within the body of the drive. When efficiently installed, the process is fast. Fully finished and packaged batches of 1,000 or 2,000 discs can be produced in 2 to 3 working days which is ideal for short notice orders and projects with tight time constraints.

Mass CD Duplication

Businesses offering a CD duplication service use duplication towers to produce many copies from a master CD. These duplication towers range in size from a unit holding 3 optical drives, similar to the unit found in a desktop PC, to much larger towers holding 4 or even 5 banks of 10 drives. Larger scale business that regularly carry out duplication for batches of 1000 or more CDs will have a suite containing many of these larger duplication towers connected in a daisy chain fashion using a firewire or high speed USB connection. Whatever the size of the suite, all of the drives will be connected to a central controlling master drive. The CD master containing the information to be copied onto all of the blank CDRs is placed into this master drive.

Obviously, when producing a batch of 1,000 or more CDs, the more towers there are available the faster the job can be completed. To aid with the speed of the process, a large scale operation will use an automated system for loading and unloading drives. Each tower will have 2 spindles located next to it. One spindle contains the blank CDRs waiting to be loaded into the towers and the other will be used to place the finished disks on as the burning process is completed. Initially all the tower drives will have their trays extended ready to receive a blank disc. An automated robotic arm will then lift the blank disks from the waiting spindle, using a rubber suction cup system to avoid potential damage to the disc top surface if it has been printed, and then load the disks into their trays.

Once the burning process is completed the drive trays open and the disks are removed, placed onto the completed disc spindle and are then replaced with fresh blank disks. The tower drives are all loaded and unloaded simultaneously by the automated system; a process that would take far longer to carry out by hand and which would be sentenced to potential human error as each disc would have to be unloaded and replaced individually. If the suite contains a hundred or more drives manual loading would be completely impractical not to mention tedious!

Duplication Suite Maintenance
CD duplication suites require relatively little maintenance. There will be a dust extraction system in place which reduces the amount of dust floating around in the air and thus eliminating any risk of dust interfering with the process. The dust free atmosphere also ensures that the electronic systems last longer as most electronic failures happen due to heat build-up due to dust. Periodically, the optical drives will need to be replaced as the laser power output drops with age. This is important as a disc burnt with an ineffective laser may have a reduced readable life.

Audio CD Duplication

Audio CDs are created using the "Track at Once" recording mode which burns each track individually separated by a short gap, usually about 2 seconds.

Producing a Master – When considering mass duplication of audio CDs it is important to bear in mind that the end result will only ever be as good as the content of the master CD. Very often the artist will probably have spent many hours composing and recording music or spoken word tracks for the project and so it will be especially important to plan for and end up with the best possible master project budget and time constraints will allow. It goes without question that the master CD needs to be a high quality disc.

Copyright – Copyright is secured for each audio track and checked for copyright infringement if any samples are used from other artist's music. Visit or for further information.

ISRC Codes – Each track needs an accompaniment ISRC code (International Standard Recording Code). These are codes that will uniquely identify a sound recording. ISRC codes are 12 characters long and contain identifiers for the country of origin, the registrant's label, the year of the recording and a unique song code. A typical ISRC code will look something like this GB-ZUY-15-00256 and your recording engineer should be able to arrange for codes for each separate track. Should your audio tracks have been assigned ISRC codes, but your master has been burnt without the accompaniment code, they can be inserted before the master is used to burn any CD copies.

CD Text – CD Text can also be added to the master so that CD playback devices that are capable of displaying text can show the track number, artist and song title.

Gracenote Database Entry – The ISRC code for each track and track title are entered into the Gracenote database which results in the CD contents being recognized by broadly used software such as iTunes.

Data CD Duplication – The master for a data CD is an identical more simple matter. The master is created and tested and as long it is performing as required, ie the autorun file runs correctly when the disc is loaded into a PC or laptop drive, then duplication can be carried out. Data CDs are produced using the "Disc at Once" recording mode which copies all the data from the master to the blank disc in one session.

Copy Protection – If the CD is destined for a retail environment or if it contains copymitted or sensitive information, then a copy protection method may be required. Copy protection can be provided by such systems as Cactus Data Shield, Copy Control, and Data Position Measurement.

CD Duplication or CD Replication?

These two processes are often confused and the two terms often get used to describe the same requirement. Using systems such as those described above, CD duplication becomes the fastest method of producing batches of between 200 and 5000 CDs but not the most cost effective. The other main method of mass producing copies of a CD, CD replication, is an entirely different process. Replication involves the individual molding of each disc rather than information being burnt onto pre-purchased blank disks. Due to the complexities of the replication process it can take far longer to produce a run of disks but the material costs are very low resulting in a lower unit cost.

Source by Lee E Brannon

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