MIDI stands for 'Musical Instruments Digital Interface'. It is a system, worked out by a Committee, for coding music and other sound signals into a file form (called 'xxxxx.mid') which enables real-time playback, as music. There are thousands of MIDI music files on the Internet, classical, pop, jazz, what you will. You can download them, mostly free.

The advantages of MIDI playback are:

1: The files are very small (as compared with .WAV and even MP3 files)

2: No background sound. Given an adequate soundcard, silence in a MIDI file plays back as complete silence - no hiss, no crackle - if you hear hum it is something to do with the electrical wiring of your computer or its proximity to other equipment, and can be cured.

3: Wide dynamic level (difference between very loud and very soft) - wider than on a CD or MP3 file, either of which is likely to have been recorded using a compressed dynamic range.

4: MIDI playback does not need a particularly fast or expensive computer.

5: If you are interested in creating your own MIDI compositions, it is easy - and very educational - to open up other people's music files and study them, to find out 'how they do it'.

The disadvantages of MIDI playback are:

1: The sound quality depends heavily on the quality of the soundcard used. A soundcard good enough to satisfy a discerning music-lover is expensive.

Playback of MIDI files

To listen to a '. mid' file, you need (i) a soundcard in your PC, (i) MIDI playback software and (iii) correct configuiration.

The soundcard

The soundcard can read MIDI music files and generate electrical wave forms according to the codes read. These wave forms, when amplified and output to speakers, simulate simulate the sound ( or 'voice') of musical instruments - even a cheap soundcard witl have a minimum of 128 different voices. The resulting mixture is heard as music. The quality of the musical sound depends largely on the way the voices are generated. Most computers are sold nowadays with a built-in soundcard which may have a fairly primitive voice generator. This will produce 'plinking and plonking' sounds, a little like music, good enough for accompanying computer games perhaps, To simulate music convincingly, it is necessary to disable the cheap on-board sound device and install a better quality soundcard.

Because of the great variety of soundcards available, each with its own voice-producing system, a MIDI music file will sound slightly different on each. The MIDI music composer or arranger has no control over this variation - the music he has coded may sound perfect on his system, but flawed or unrecognisable on others. This is why MIDI, as a means of listening to music for entertainment, has been largely replaced by MP3 and other systems which record the exact music as compressed wave forms.

The soundcard I have in my PC is old and cheap - a Creative SB16. By itself it produces low quality music from MIDI files. This does not matter because in my system, it is used only as an input and output device for MIDI playback and composition, and as a small mixer and amplifier. The actual sounds are produced by a linked Yamaha SW60XG 'wavetable' card, which has no MIDI but automatically links itself to the 'host' card's MIDI, providing accurate and beautifully realistic instrumental voices.

S-YG20 is a software version also using a Yamaha voice system. I think it can be downloaded from the Yamaha site on free trial for 90 days, after which it ceases to operate. I tried it and the sounds were just like the SW60XG, but my PC was too slow for it to operate perfectly. It does include a midi driver and player.

MIDI playback software

Your computer will almost certainly have at least one MIDI player on it. If you have installed Winamp for MP3 playback, it can be used as a MIDI player as well.

I you click on Explorer > View > Options > File Types you can, with some difficulty, find out what player Windows will use for .MID files supposing you double click on a .MID file name.

Troubles with MIDI playback

The MIDI files in my collection should play back straightaway through your browser, which will have configured itself to do so when it was installed. All you should need to do is to click the MIDI PLAY button on the left hand side of the screen showing the picture for the music piece. If you hear nothing, check the volume controls on your amplifier/speakers first. Then check the on-screen mixer which is part of your soundcard's control system - the slider for MIDI play should be slid up.

If still nothing, next examine your browser. In Netscape, click Edit > Preferences > Navigator > Applications - if you browse through the list of Descriptions, you won't find one labelled MIDI, but eventually you will find one which says under File Type Details, Extension: MID, and underneath that, Handled By: .... and then you will see the name of the application that the browser wants to use for MIDI playback. If you think the setting is wrong, it is possible to alter it by clicking on Edit > Browse (you can leave the box for MIME type blank); you may have to experiment. If this does not work, look in the Plugins subdirectory of the directory which contains Netscape. The plugins should include at least npaudio.dll (if not, you will have to get it) and possibly npmidi32.dll as well. If you cannot get things right, reinstalling Netscape may work, and be quicker in the long run.

f there is still no music, Charles Belov's MIDI Web Tips Home Page is the most comprehensive and helpful site I know of for information relating to Midi on the Web. It has diagnostics including a magical facility which will test your browser in a flash, and tell you just what arrangements you have (or lack) for playback of MIDI music! If you consult Mr. Belov's site, click on 'Tests' to go to his MIDI Plug-in Test Suite. This section tests a browser or MIDI plug-in's behavior when given various HTML instructions.

If all else fails, you can still hear MIDI music by downloading the .mid file to a directory on your hard drive (.mid files for download from my site are in .zip form, so you must unzip them with Winzip). Then you open up one of your MIDI players, and select the .mid file for playback. This always works.