Although the two words essentially have the same meaning, in the optical disc industry, there is a big distinction in the terms, and how they refer to the manufacturing process of the final discs.
Duplication: Manufacture of discs using blank CD-R, DVD-R, Blu-ray-R (BD-R).
Replication: Manufacture of the discs from stamper and glass-master, pressed from polycarbonate granules.
For duplication, blank media is used, for example, such as mentioned above and data or audio files are copied onto the disc. The discs are then printed. In the CD replication or DVD replication process, a glass-master and stamper are made for the required content, which is like a master copy. From this stamper, the discs are ‘pressed’, similar to an injection moulding process, where the disc starts off in its raw form as polycarbonate granules.
Advantages: Duplication is cost-effective on 1-400 copies, or when a fast turnaround is required. Replication is cheaper to manufacture once the quantity is 500 or more, and the final discs are considered professionally manufactured discs.
There is no difference in the sound quality of audio CD, or any difference in the quality of the data copied on the discs between duplicated and replicated discs.