Introduction to MIDI and MIDI Files
M.I.D.I. = Musical Instrument Digital Interface
Author – John Ialuna, Founder and Creative Director @ Hit Trax MIDI
About MIDI .. a brief history
MIDI was created in 1983. The ‘Interface’ is designed to connect any number of synthesizers, samplers, drum machines and sound modules to a MIDI Sequencer and enable digital recording of music. MIDI is simply the link between musical instruments and computers to send and receive instructions to each other.
Early popular MIDI instruments included the Yamaha DX7, Ensoniq ESQ 1 and Mirage and Roland Corporation’s Jupiter 6 and TR-909 drum machine. There were others of course, all incredibly expensive and most would only play 8 notes at a time.
In 1986, Roland Corporation released the popular MC-500 micro composer sequencer, a floppy disc based 4 track MIDI recorder. Yamaha followed soon after with the QX series, along with offerings from Kawai, Alesis, Korg and Akai. Looking back, the new ‘sequencers’ as they were known then, were primitive. They were expensive, used floppy disks (computer recording was still to be invented), finicky and technically challenging. On the other hand, they were innovative, eventually evolving into DAW’s (Digital Work Stations) and todays popular programs and apps like Logic, Pro Tools, Cubase and Sonar.
One MIDI controller keyboard can control many devices (up to 16). Simply allocate a MIDI channel to a connected device and set the same channel on the controller to ‘trigger’ the selected sound in the receiving device. These days, it’s uncommon to see many units daisy-chained together. This is due to computers being more powerful and efficient than those available in the early days of MIDI.
How MIDI Works
MIDI simply sends messages from one device to another. The sending device could be a MIDI keyboard, synthesizer, MIDI drum sets or a sound module and the receiving device a computer program like Cakewalk, Sonar, Logic or a stand alone disk based Sequencer.
Song data is saved as a SMF ‘Standard MIDI File’ with the extension .MID (example, MySong.MID). The most popular method to create and edit MIDI data is using a computer program. A MIDI keyboard is connected to the computer by a MIDI Interface, USB or Firewire and the ‘Sequencer Program’ records, processes and edits the song data. Some typical edits include:
- Adjusting individual or multiple notes loudness, position, note lengths
- Instrument panning, reverb and overall volume levels
- Changing the instrument to another
- Transposing to another key
Where do the sounds come from?
Most Sequencing programs like Logic, Cubase, Sonar, Pro Tools and so on have built in VST (Virtual Studio technology). Apple’s popular Logic Pro (and Logic Express) have their own EXS24 sample library. Sounds can be sent to a MIDI Sequencer from a MIDI sound module. These devices vary in quality and the good ones like M-Live’s MERISH PLUS, the Roland BK-5 and top end models from Yamaha and Korg have on board sounds, editing and features suitable in the studio and as a backing track sound module for live performance. Typically, the MIDI sound modules are more popular with solo artists, duo’s/trios etc using MIDI backing tracks during performances.
MIDI Sounds then and now
When MIDI began in 1983, every manufacturer had their own sounds programmed into their synths. A sound could be a piano, bass, electric guitar, organ and so on. Each sound was represented by a program number. The user would dial up the program number and the sound would load into the device. This concept worked for a short time until musicians, as they do, began collaborating on projects. They discovered that synths from different manufactures didn’t always match the program number with the same sounds. A piano with program number 001 assigned on your synth might not correspond to the trumpet assigned to program number 001 on my synth. Thankfully, the music industry put their heads together and agreed on standardised format for MIDI sounds and ‘General MIDI’ was born
General MIDI (GM) was developed and released in 1991 by the MIDI Manufacturers Association (MMA) and Japan MIDI Standards Committee (JMSC). In a nutshell, the specification called on all manufacturers to design and build their instruments to a pre determined set of 128 instrument and drum kit sounds, minimum 24 simultaneous notes, respond to note velocity and several points of compliance.
The idea was to ensure collaborating musicians, and later, producers of licensed MIDI Files could create MIDI Files that would ‘load & play’ in any GM device. Miraculously, all the major musical instrument makers agreed and complied with the GM format.
General MIDI and modern music
This was an important moment. All of today’s modern apps, programs and sound libraries are a direct result of this industry agreement. Had GM been rejected, modern music would certainly have taken a different course. The advent of smaller bands combining live instruments and backing tracks may never have happened. Dance/techno music would be 20 years behind and so on. All said, it was a good move.
Instrument manufactures were not limited to GM. Many included their own additional sounds and features and included Gm as a separate feature in their devices.
Recording a MIDI File
You can have a lot of fun creating your own MIDI backing track or editing & tweaking a professional MIDI file to your personal taste. Sequencing software Logic, Pro Tools, Cubase and Sonar have a powerful tool for the music creator and best of all, they are easy to use – even if you are not very proficient at playing a keyboard.
The Sequencer records and plays back the musicians performance or you can input the data note by note using a step-editor. each performance is recorded and stored on a dedicated track and assigned a channel. You can use up to 16 channels in GM.
MIDI channel and Tracks
General MIDI can use up to 16 ‘channels’ simultaneously however a SMF can have unlimited tracks. How does this work? Let’s say we are recording drums. Drums are always recorded to MIDI channel 10. On our sequencer, we’ll create a track and assign it to channel 10 then record the kick drum. Then we can create a new track, also assign it to channel 10 and record the snare part. Repeat the process and we record the hi-hats and so on. it’s not uncommon the have 8 or more individual tracks dedicated totally to drum parts and have all these ‘tracks’ assigned to ‘channel 10′.
SMF format 0 and SMF format 1
SMF’s (Standard MIDI File’s) can be saved in 2 formats, Type 0 and Type 1. Both will work exactly the same. The differences in the formats are:
- SMF type 0 are merged and stored on a single track assigned to a master track (not channel 1-16). SMF format 0 were popular in the early days of MIDI when floppy disk sequencers had limited reading capacity. Having all MIDI channels merged into one readable track made these early devices more reliable.
- SMF type 1 retains all the individual tracks in their original ‘split’ format. Almost all sequencing programs will automatically load a SMF and split the tracks, regardless of whether they are type 0 or type 1. Musicians generally prefer to work with type 1 SMF as they can see all the tracks individually.
What are MIDI Controllers?
Each channel has a series of ‘controllers’ also known as CC’s (Continuous Controllers). There are 127 CC’s, but typically, the ones you will mostly see and edit are:
- CC 7 – Volume
- CC10 - Pan
- CC11 – Expression
- CC91 – Reverb level
- CC93 – Chorus level
MIDI is not …
MIDI is not ‘sounds’. It’s important to remember this important fact. MIDI simply sends and receives messages. It is the sending and receiving devices that interpret the messages embedded in the MIDI File that reproduces the song file or other event the MIDI File is programmed to activate.
Thanks for reading my blog. Send me questions through the contact page at the foot of this page. I can usually respond same day (weekdays) or next business day.
General MIDI – look up General MIDI
General MIDI Instrument Sounds – look up GM sounds
VST (Virtual Studio Technology) - look up VST
Logic EXS24 Samples – look up Logic EXS24
Logic EXS24 Samples (more) - look up Logic EXS24
Backing Track Players
Merish PLUS MIDI and Mp3 backing track player - View products online
Roland Backing Track Players - View products online
Korg Backing Track Players - View products online
Yamaha Backing Track Players - View products online
Other MIDI Resources
Logic Pro sequencing software for MAC - View product web site
Sonar and Cakewalk sequencing software for PC - View product web site
Cubase Pro sequencing software for PC and MAC - View product web site
Nuendo, Sequel and VST sequencing software for PC and MAC - View product web site
MIDI Manufacturers Association (MMA) for some images – MMA web site
(C) 2013 John Ialuna (Hit Trax MIDI Files)