21.1.09

Analog-Digital Audio - Understanding Audio

Audio needs to be digitised so that the computer can process it, but rendered as analog so you can hear it. Hence there's a lot of calculation to be done via Analog/Digital converters (A/D converters). The prime components are as follows...

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Analog connectors
Analog to Digital convertors accept a wide variety of audio plugs, from mini jacks on gaming soundcards, to 1/4 inch phone jacks on semi-pro kit to 3-pin XLRs.
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Digital connectors
Many audio devices cut analog out of the chain by offering digital audio connections via Phono plugs and optical cables.
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Audio as data
The waveform of a small chunk of digital audio. This picture is zoomed in so close, you can actually see the steps of the sample rate: 44.1 kHz, which is CD quality audio.
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We all have CD players, which read the binary code stored on compact discs and convert it into electronic signals that waggle speaker diaphragms in an analog representation of a disc's data. All this diaphragm waggling creates compression and rarefaction of air, which in turn waggles our eardrums and that is how we perceive sound. Now lets try it in reverse.

When you holler into a microphone, the mic's diaphragm waggles and the movement is converted into electrical fluctuations representing as analog of the sound you're making. If the mic is plugged into an analog to digital coverter such as the computers soundcard, the electrical signals can be encoded into digital form and recorded to the hard drive. In fact, any analog audio source can be digitised, be it from a record player, guitar or hardware synthesizer. Just like sequences of MIDI data, multiple recordings of digital audio can be recorded to, and played back simultaneously from, multiple tracks, so there's plenty of potential. Especially when you run MIDI in synchronization with the audio.
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1 comments:

Reese said...

Great info on this site. You actually helped me a lot on the paper I'm writing. Keep it up and thanks!