MIDI stands for 'Musical Instrument Digital Interface'. What follows is a brief introduction to it and its peculiarities in the context of ringtones.
In days of old, most music was written on paper, and to hear the music you'd also need a musician and an instrument, lets say its a piano. The musician would read the music and play the piano, and music would flow forth, to enchant elegant gentlefolk in posh hats or give cowboys and whores something to dance to.
Then some bright spark had the idea of doing away with the musician (seeing as we're all good for nothing drug addicts) and inventing the 'player piano'. This infernal device played the hits of the day using a roll of punched paper, with the holes in it representing the notes. The same approach was used in fairground organs and such like.
Fast forward to the present day, replace the piano with a synthesizer. Its still an instrument, and a musician can still sit, read from music and play it for us. If the synthesizer is MIDI compatible, we can also connect up a MIDI player to it, which may be a standalone device or a PC, Mac, Atari etc. If we then take a MIDI file for a particular bit of music, the synth can then be played using this file, which is the modern day equivalent of the roll of punched paper used by the player piano. MIDI files are written and played in programs called 'sequencers', though the sequencers on some devices (including most phones) are playback only.
The important thing to remember here is that the music that is produced by the synth is not a recording of the music as you'd listen to on an album or the radio - its an instrument being played and the information used takes the form of instructions to play a specific note, at a specific volume for a specific amount of time. There are more instructions that can be conveyed by MIDI, such as which type of instrument to use.
While MIDI information can be used for anything (for instance, a MIDI file of a string quartet could be used to play a synth set up to play horn sounds), there are some agreed standard sets of instruments, and the one that interests us is 'General MIDI' or GM.
GM is a set of 128 instrument definitions:
Piano: 1 Acoustic piano 2 Bright piano 3 Grand piano 4 Honky-tonk piano 5 Rhodes piano 1 6 Chorused piano 2 7 Harpsichord 8 Clavinet Chromatic Percussion: 9 Celesta 10 Glockenspiel 11 Music box 12 Vibraphone 13 Marimba 14 Xylophone 15 Tubular bell 16 Dulcimer Organ: 17 Hammmond organ 18 Percussive organ 19 Rock organ 20 Church organ 21 Reed organ 22 Accordion 23 Harmonica 24 Tango accordion Guitar: 25 Acoustic nylon guitar 26 Acoustic steel guitar 27 Jazz guitar 28 Clean guitar 29 Muted guitar 30 Overdriven guitar 31 Distortion guitar 32 Guitar harmonics |
Bass: 33 Acoustic bass 34 Finger bass 35 Picked bass 36 Fretless bass 37 Slap bass 1 38 Slap bass 2 39 Synth bass 1 40 Synth bass 2 Strings: 41 Violin 42 Viola 43 Cello 44 Double bass 45 Tremolo strings 46 Pizzicato strings 47 Orchestral harp 48 Timpani Ensemble: 49 Strings 1 50 Strings 2 51 Synth strings 1 52 Synth strings 2 53 Voice aahs 54 Voice oohs 55 Synth voice 56 Orchestra hit Brass: 57 Trumpet 58 Trombone 59 Tuba 60 Muted trumpet 61 French horn 62 Brass 63 Synth brass 1 64 Synth brass 2 |
Reed: 65 Soprano sax 66 Alto sax 67 Tenor sax 68 Baritone sax 69 Oboe 70 English horn 71 Bassoon 72 Clarinet Pipe: 73 Piccolo 74 Flute 75 Recorder 76 Pan flute 77 Bottle blow 78 Shakuhachi 79 Whistle 80 Ocarina Synth Lead: 81 Square wave 82 Sawtooth 83 Calliope 84 Chiff lead 85 Charang 86 Solo synth lead 87 Bright saw 88 Bass and lead Synth Pad: 89 Fantasia 90 Warm pad 91 Poly synth 92 Space pad 93 Bowed glass 94 Metal 95 Halo pad 96 Sweep pad |
Synth Effects: 97 Ice rain 98 Soundtrack 99 Crystal 100 Atmosphere 101 Brightness 102 Goblin 103 Echo drops 104 Star theme Ethnic: 105 Sitar 106 Banjo 107 Shamisen 108 Koto 109 Kalimba 110 Bagpipe 111 Fiddle 112 Shanai Percussive: 113 Tinkle bell 114 Agog 115 Steel drums 116 Woodblock 117 Taiko drum 118 Melodic tom 119 Synth drum 120 Reverse cymbal Sound effects: 121 Guitar fret 122 Breath 123 Seashore 124 Bird tweet 125 Telephone Ring 126 Helicopter 127 Applause 128 Gunshot |
It should be noted now that inside your phone is a synthesizer chip which is able to play MIDI files via its inbuilt sequencer. These files can be loaded into your phone by a variety of means.
The sound quality and abilities of this chip varies enormously, but by and large they can all play these 128 different sounds or 'patches', as well as some percussion sounds. The term 'Polyphony' refers to playing several notes at the same time, which may be one or several instruments at once. Early phones often had a polyphony of 4 'voices', but now there are phones that have polyphony of up to 128 voices.
'Polyphonic' and 'Poly' are also the terms used to describe the type of ringtone a particular phone can play. If a ringtone uses more polyphony than the phone its being played on can handle, we can encounter 'note stealing', where the phone will start dropping notes. More about this in technical aspects of MIDI for ringtones.
MIDI uses 16 different 'channels' to organise different instruments, and these can broadly be thought of as similar to the channels in an audio mixing desk, with one recorded track per channel. Channel 10 is usually reserved for percussion (drum) sounds. MIDI drums differ from the normal instrument patches. It can be thought of as a single patch but with a different percussion instrument on each note. Again, different synth chips vary enourmously as to the quality and amount of drum sounds available, but the most popular sounds (such as the basic drum kit of bass, snare, cymbals and toms) are usually there.
So we now have a platform where we can take a MIDI file for a particular bit of music, which tells whatever MIDI device its played on (in our case a mobile phone) what to play and with what instrument. The limitations of this with regards to using it to play your favourite music is obvious. No vocals and only the roughest approximation of the actual sound on the track, nevermind the subtleties of the production.
So why go to all the bother of getting someone to write a MIDI file when you could just play a recording of the song as an MP3, WAV or other format (called music ring tones, voice tones, mastertones, realtones, singtones or true tones).
1: Its only in the last few years that phones have been able to play back recordings. For a while MIDI was king.
2: Size matters (apparently). In terms of data, a MIDI file for 30 seconds of music is tiny compared to even the most compressed and therefore crappy audio recording. Its changed from the early days, but it used to cost a lot more to deliver true tones.
3: Royalties are funny things. There are different types of royalties payable to artists, and the kind paid from playing or selling copies of an actual recording are much more than those from making and selling MIDI representations of it. This, combined with the delivery charge means a recorded ringtone is going to cost the company you buy it from, and therefore you, more. This doesn't apply to truetones created by ringtone companies themselves, such as novelty noises.
The MIDI ringtone market is in decline, thats a fact. As more phones incorporate MP3 players which allow the user to play whatever they like as a ringtone, its going to decline more, but its still there and it still has its uses. New phones are still built with MIDI capability. MIDI in the field of professional music is still the de facto standard way of controlling one device from another and will be around for a long while yet.