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2.2 Content media

2.2.2 Digital mode: Audio files

 

Compact disc (CD)

 

Compact disc (CD)

As with any digital format, the main risk involved in conserving digital audio files is obsolescence of the format. However, market domination by the compact disc (CD) seems far from losing steam. A few higher quality audio formats (super audio CD, audio DVD) have made relatively unsuccessful forays into the market, and the compact disc is still widely used by artists.

 

CDs should be conserved in conditions where humidity, light (darkness) and temperature can all be controlled (see table below), but above all, they should be copied in their original format to a computer. Unlike the CD pressed in the factory, the CD-R (recordable) has a short lifespan. [1] For this reason, it should be migrated and not made part of any archiving plan. The best conservation strategy for a digital format is redundancy of the copies, i.e. store copies of the same document in different locations and formats. For example, a compact disc can be physically stored in a vault, in a local computer as a raw .AIFF file, or on a server as an open source audio file.

 

Recommended temperature and degree of saturation for optical storage media [2]
Temperature ±/24h ±/year Relative humidity ±/24h ±/year
Optical storage medium

autour de 20 °C

±1 °C ±3 °C 40 %

±5 °C

±5 °C

 

 


[1] According to Kurt Gerecke, a physicist and storage expert at IBM Deutschland GmbH, the lifespan of CDs burned on a computer is five years at the most. He adds that even if the CDs are stored in ideal conditions, the time gained will be minimal. However, Gerecke’s statements have been considered as somewhat alarmist:

http://www.computerworld.com/s/article/107607/Storage_expert_warns_of_short_life_span_for_burned_CDs
[2] George Boston. Memory of the World: safeguarding the documentary heritage: a guide to standards, recommended practices and reference literature related to the preservation of documents of all kinds. 1998 [PDF]:

http://portal.unesco.org/ci/en/ev.php-URL_ID=2168&URL_DO=DO_TOPIC&URL_SECTION=201.html