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.
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 businesses 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 discs 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 discs 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 discs into their trays.
Once the burning process is completed the drive trays open and the discs are removed, placed onto the completed disc spindle and are then replaced with fresh blank discs. 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 prone 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!
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 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 that project budget and time constraints will allow. It goes without question that the master CD needs to be a high quality disc.