3. Digitising audio: an outline 3.1. What is digitisation? Digitisation is converting something into digital or numerical form. Usually this means taking something which exists in a physical medium and making a digital copy or representation of it; this digital copy can then be stored, manipulated and distributed electronically, without the need for any physical medium. A photograph, for instance, is an image on paper. By digitising, we convert the image into numbers which can be stored on computer. The collection of numbers represents the image: it is a copy. We no longer need to deal with the photographic paper in order to view the image. Similarly, we can digitise sound recordings which might be on magnetic tape, for example. By digitising, we convert the sound into numbers which can be stored on computer. The collection of numbers represents the sound: it is a copy. We no longer need to deal with magnetic tape in order to listen to the sound. 3.2. Why digitise sound recordings? Digital copies of recordings have some important advantages over analogue ones: Digital copies are infinitely repeatable: once in the digital domain, further copies can be made without loss of quality. Analogue tape-to-tape copies, for instance, degrade with each generation. Digital copies are easily stored: a computer can store huge quantities of digital sound obviating the need for bulky archives of tapes or disks. Digital copies do not degrade in a way which affects sound quality: when analogue media degrade, sound quality is lost, such as when records become scratched. Constant sound quality is maintained throughout the life of a digital copy. Digital data may be searched easily: a computer can be used to perform complex searches on large collections of sounds very quickly. 3.3. What are the pitfalls? 'Digital' is not synonymous with 'high quality': this is sometimes falsely implied. Digital audio can be of lower quality than analogue audio. In some cases, digitisation of a recording can reduce sound quality. A good digital copy is one which captures as much information from the original as possible, even if the original is badly degraded. There are ways to improve the perceived sound quality of a recording once digitised. This will be discussed in section 7.5. Copyright is easily infringed: once digitised, the ease of making further copies and distributing them (particularly via the internet) means it is very easy to infringe copyright. This is currently a major source of concern within the commercial music industry. It is vital to ensure you are working within the law. This topic has been covered in chapter 2. Digital copies still rely on some storage medium (such as computer hard disk or compact disk), which are themselves subject to physical degradation. Though degradation of digital media does not result in progressive loss of sound quality, it may eventually render data unusable. This need never be a problem, as electronic data are easily preserved by making backup copies. This is covered in chapter 10. 3.4. What resources are needed to digitise audio? Equipment The equipment you will need depends on the medium of your original recordings. In general, you will need a machine to play back the recordings and a machine to make the digital copies (usually a computer). In some cases this will be all the equipment you need, in others the requirement will be more complex; some tasks may need highly specialised equipment, and possibly dedicated space such as a recording studio. Equipment is discussed more fully in chapters 4, 5 and 7. Time You will need to allow plenty of time for digitisation. Precisely how much will vary with each individual case: for example, some projects may involve preparation of specialised equipment, whereas others may use a straightforward technical setup. The time requirement is discussed in section 6.2. Skills You may have the necessary expertise to carry out your digitisation project, or you may need assistance from other individuals or agencies. This obviously has funding and time implications which will need to be thoroughly considered beforehand. This is discussed in section 6.1. Top of Page
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