Icons 30 November 2021 2 min

And the disc became compact!

Relegated to the bottom of our drawers, they clutter up our lives and yet, like books, it is difficult to part with them. Now replaced by streaming music, the compact disc, known as a CD, had its moment of glory.

Within a decade, it had overtaken vinyl records as the most sophisticated and popular way to store data in digital form, free of dust and scratches. It will be 40 years old in 2022!

Purity of sound, a revolution for music lovers

A unique collaboration between Philips, Sony and Hitachi, the first CDs were invented in 1979 and first sold on 17 August 1982. They were small flat polycarbonate discs and were aimed at a music-loving audience, more inclined towards classical music. It must be said that the CD has arguments in its favour: no wear and tear on the disc due to the absence of mechanical contact, minimal space requirements, no background noise and a very pure sound.

Polycarbonate was chosen for making CDs because of its properties such as optical purity, transparency and a constant refractive index. These mass-produced discs, whose surface is covered with pits in a spiral pattern, are engraved with data and then metallised with a 40-50nm layer of aluminium. They are read by a laser beam directed from the centre outwards. The disc, which is insensitive to dust and scratches, rotates counter-clockwise. The result is a very pure sound.

74 minutes of music stored in small 12 cm plastic discs

CDs are small, measuring 12 cm in diameter instead of the original 11.5 cm. Legend has it that conductor Herbert von Karajan requested that the CD be able to hold 74 minutes of music - instead of 60 minutes on 11.5cm - in order to hold Beethoven's 9th Symphony. It is said that the wife of Sony’s CEO supported this request.

1985: sales boom!

The CD only caught on with the general public in the second half of the 1980s. Dire Straits' Brother in Arms in 1985, the first all-digital record, is credited with making the first breakthrough. And by 1988, CD sales had overtaken vinyl in France. Ten years later, worldwide production reached 1.2 billion units.Today, putting all the CDs produced end-to-end would reach around the world six times.

In the age of streaming and dematerialisation, the CD’s popularity has somewhat waned. However, it is not impossible that a future generation will rediscover its many qualities. The vinyl record can testify to this given its resurgence in recent years.