Archives for December 2020

Inside the Compact Disc

Everyone has seen a Compact Disc, heard music played derived from one of, or used one to store files digitally. Not a lot of people discover how they work though. The CD is often a modern marvel of science that can be a true testament to the tenacity in the human spirit and ingenuity.

Creating a Compact Disc is a more involved process than many individuals realize. The data is recorded onto the disc in microscopic increments which means that during production, even the smallest particles of dust may cause the recordings to be corrupted. The manufacturing process must be very accurate and precise as there is no room for error.

Turning Binary into Sound

The first challenge was developing the disc itself. Optical discs should be in a position to contain huge amounts of data given it takes around a thousand bits to playback one second of music. Fortunately, a million bits with a Compact Disc is about the size of the head of a pin. This made optical discs the effective way to keep your data for later retrieval. Another challenge was inventing a means to read back all in the compressed information about the CD fast enough to learn back sound continuously, which was permitted by integrated circuit technology.

When a whole new audio CD is needed, a glass master must be created first. It is inspected carefully for quality assurance must be flawless master’s what is absolutely needed to manufacture good replicas. Once the glass master is completed, a stamper is created which is loaded into an injection molding machine, the location where the actual replicates are manufactured. Through every step of the manufacturing process, quality and precision have to be solidly maintained on the risk of creating waste.

A Compact Disc plays the sounds last a process of groves organized inside a spiral in the surface with the disc. When the laser from the CD player moves along the spiral, it is going to encounter “pits” and “lands” that can cause the laser to be reflected back at various intensities towards the reader. The computer inside the CD player interprets this data as sound. Using this method eliminates the “fuzz” which you might hear on some older audio recordings, making CD’s one of the most top-quality audio formats around even now.

Alternate Methods

The original formats presented in the Red Book developed by Sony and Philips were eventually discarded by many so that you can produce audio CDs which are in excess of 79.8 minutes and to be able to allow for digital rights management (DRM). Over the years music CDs are becoming for sale in 74, 80, 90, and 99-minute versions. The 80 minute CD (which is actually 79.8 minutes) is currently the standard size. However, the greater music a concise disc hold, the tighter its spiral should be (allowing to get more playback). Not all CD players are prepared for the tighter spirals, particularly the older CD players that existed prior to higher capacity discs hit the industry. Eventually, though, manufacturers updated many and then you are much unlikely to have problems playing 80-minute discs. The 99-minute discs are another story though. Your best bet would be to avoid them.