Back to  How do computers have sound?

These days, sound is very important on computers. It's all part of multi-media. We asked our computer scientist Pierre Kerr,, about this question and here is what he said.

There are several different ways that a computer can make sounds. The original PC that was introduced in 1980 had a tiny speaker that could go beep and with some clever programming could play unpleasant sounding music and computer game noises. It was pretty awful. The tecnical term to describe how that speaker worked is was a D/A or digital to analog converter. This bit of simple electronics would convert a digital number to a sound.

Modern computers have several ways of making sounds.

They still have the old speaker although they do sound a bit better now. That's all that my office computer has and it can talk and play sounds like breaking glass.

If they have a sound card, they can also play digital sounds. That is, sound that has been recorded and turned into data that can be stored on a disk. These include WAV and VOC files. They should also be able to record sounds if you can plug a microphone into the sound card. Recording sounds takes a lot of disk space however. A 1 minute recording could take up to 6 megabytes!

A much more efficient way of playing music on a computer is to us a MIDI device. MIDI stands for Musical Instrument Digital Interface and is very much like a computer language but was invented for electronic musical instruments and does not require a computer to work. There are many MIDI keyboards available and they have built-in synthesizers which actually make the musical sounds. A PC sounds card usually comes with a MIDI interface plus a simple synthesizer. A minute long MIDI piece of music could take as little as 6k of disk space and sound just like a full orchestra

There's one more possible source of sound from a computer and that will work if the PC has a CDROM drive. It is possible to play tracks of music from a CD and have it play through the speakers on your PC.

Oc course, there are computers like the MAC and Atari that have some built-in sound capabilities but these are similar to the PC. MIDI and digital recording techniques are almost the same.

I've included a copy of MONITOR magazine from last year that discusses sound on PCs. Look at page 10. Also, page 21 talks about MIDI.

Thanks for your question.

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