Digitization is very different and quite hard to get a handle on. The same sound-wave is repeatedly measured for its instant strength and the value is recorded as a binary number or code. This has to be done very quickly and a favourite standard rate is 44.1 KHz. This is to ensure that nothing of importance is missed.
The range of levels that the coding system can represent depends on the total number of digits in the number. If it was a decimal system we know that two digits can represent 99 levels, three 999, and so on. {Actually 100 & 1000 since zero is a level too}.
In the binary system each "bit" (for binary digit) can represent either a "0" or a "1" and it turns out that the numbers can get unreasonably long. 1000 levels needs 10 bits. (1024 levels actually). This doesn't fit well with the architecture of most computers and long numbers take lots of time to handle. It is common to place a limit on the maximum number of "quantities" that can be represented.
This "quantization" process can be "shifted" to represent more levels without the need of more bits. That process is not that unlike the "SHIFT" keys used on a typewriter to switch from upper to lower case letters - WITHOUT the need of more & more keys.
Advantages of the digital method:
Analogue signals can never be faithfully copied. There is always some degradation from the original. Digitized quantities can be copied exactly, and much more quickly too.
It is useful to be able to manipulate sound tracks. In a computer the binary coded signal can be pitched changed or speed changed independantly.
Cutting & patching are possible in the software.
Effects (echo, reverb, harmonoy, tremelo, vibrato) can all be added to the signal without destroying the original sound track.
The necessary physical storage space is less than with other media.
The cost of the optical media (CD/DVD) is very low.
DISADVANTAGES: -
The argument that digital sound sources are "better" is not usually true. This is because practicalities dictate that space-saving devices are used. (mp3 files). The sound quality can seem almost too clean as it is possible to remove all "noise" signals completely. It can be argued that the complex compression techniques that are used actually change the sound in subtle
ways that is not always to the listeners liking.
The jury is still out on digital longevity. The old bakelite & celluloid records will take some beating in that respect with some still playing after 100 years. It isn't thought that CD/DVD life will be anything like that long. The compact nature of the track data militates against a long term life. Flash memories have only a 10 yr life. The magentic stores might fare a little better in this respect.
Comapatibility has always ben an issue. Phonographs, gramophones, record players, reel to reel and cassette tape machines have all had a turn. With digital both the media and the software format might be overtaken. While common software formats may be maintained & even regenerated fairly easily, it is the hardware that poses the biggest problem. Where would you now go, for example, to get played one of the original 7" floppy disks from the 1980's? The 5.25" format is also gone. Even a 3.5" FDD is getting hard to find now. What will the future bring?
