MIDI

MIDI and home computer music composition and performance

Guest speakers: Perry Williams and Chris Vessey

October 21,1996 7:00 PM

Location: 4th floor, lounge, AtlanticVetrinary College, University of Prince Edward Island

Chris Vessey discussed the MOD system. He compared it with MIDI as well as demonstrated it (to everyone's enjoyment). He fielded many questions and stayed after the meeting to further demonstrate MOD. He offered a handout (MIDI vs. MOD Comparison of Operating Theories) to accompany his presentation.

Comparison of Operating Theories MIDI vs. MOD

MIDI: Musical Instrument Digital Interface

MIDI is actually a communications standard for attaching appropriately equipped musical instruments (generally synthesizers and drum machines) to each other, to permit sharing of music information and central control. MIDI also permits the connection of these instruments to a personal computer.

In the latter case, the computer can perform one of several functions:

Recording from external devices: the computer can record a musician's performance, store it and permit it to be edited, or rendered in manuscript format.

Playback to external devices: the computer can take pre-recorded MIDI data and send it to an instrument, thereby replicating a previously recorded performance.

Storage and Editing: As mentioned above, a given performance can be recorded, and stored. This allows performers to record their portions of a musical composition at discrete times, and then combine their performance data sets at a later time. Also, any "errors" within the performance can be edited, so that during playback they simply do not occur. This editing feature is what truly makes MIDI different from conventional multi-track recording schemes.

It should be noted that, although a performer may record a performance on a small MIDI synthesizer, the playback could occur through a MIDI-equipped grand piano. It is not necessary that the recording instrument be the same as the playback instrument.

At its heart, MIDI is simply a standard for the way in which instruments and computers are connected, and how the information is passed between these systems. In other words, the computer handles the data, and the instruments handle the acquisition and performance.

For this reason, MIDI data can be transferred from one system to another, but the music will have to be "re-voiced"; different anufacturers make different voice sets for their keyboards; many of these follow no set standard in how these voices are rganized. Thus, something recorded on one combination of instruments may sound completely hideous when played on another instrument set. For this reason, MIDI data is only semi-portable between systems. However, in recent years, manufacturers are beginning to follow a basic "General MIDI Standard" which will permit greater portability between systems (i.e. the voice entries for pipe organ will be located in the same memory bank on each system).

Pro grams which handle MIDI data are usually called MIDI Sequencers, since they put musical data into appropriate sequence, but are sometimes called MIDI Track Editors because they record the several "tracks" of MIDI data and allow them to be edited and mixed. Personal computers containing sound cards (like a Soundblaster) can control external MIDI devices; however, they can also be set up to "simulate" external MIDI devices with their on-board oscillator sets, so it is possible to play MIDI music without any external MIDI interface or devices.

MOD: Music Module Tracker

A MOD system is fundamentally similar, but in fact quite different, from a standard MIDI system. Where a MIDI system generally interacts with external devices, a MOD system is designed to work specifically with a personal computer's sound card.

The MOD system was never developed with musicians in mind - it was created for the world of computer games. Game creators needed a way to produce music that was simple, effective, produced high-quality sound, was completely portable between systems, and did not require large amounts of computer resources (most of the music played as backgrounds to action games; to slow down the computer would be to slow down the game).

MOD was modelled after the MIDI data standard. In other words, it took MIDI's strongest point, the ability to record, edit and play back music from a data file, and sought a method of overcoming its weakest point, its limited portability. To do this, some assumptions about how the data was to be organized had to be made: it could not be assumed that all instrument sets would be the same, so it was necessary to provide a method of storing the instruments as part of the data file; and, since the only common denominator was a standard PC sound card, that had to be the sole output device. This was the only way to ensure that a game didn't sound ghastly as it was used on different brands of PC.

The MOD system thus allowed a computer composer to use digitized sounds through a system-standard sound output. device,. with data which closely resembles that used in MIDI. This data, incidentally, is known as event data - an event is something which causes a sound to be made, to be changed, or to be stopped, or which controls the general playback of sound.

Because MODs were generally used by programmer-types, the format is essentially non-musical.The notation refers to standard musical note names, but it is not readable in the manner that manuscript is readable. It is important to understand that this data most closely resembles the actual MIDI data recorded on a MIDI system - the manuscript format is simply an ability of the computer to quantize the recorded events into the discrete notation system preferred by musicians. Since the MOD system was not designed for musicians, it lacks this notation system.

MOD files are extremely portable. So much so, in fact, that they are compatible not only between brands of IBM-type PCs, but with other completely different systems. The MOD format was originally designed on the Commodore Amiga platform; it is now portable to IBM, Apple and Unix formats, to name a few. It is completely normal to take a MOD file created on an Amiga computer, and simply by transferring it to a PC with no translation of the data (just a change of disk format), the data is usable on an IBM system. Since the instrument voices are actually digitized and stored with the music, we find that we have a device independent method of transferring music data.

Newer "tracker"' programs now have many enhanced features, such as:

internal sound sampling and editing via the system's sound facility
recording of event data from a MIDI input device (makes life a little easier for musicians)
extended MOD formats which, while less portable, offer a significant number of desirable new abilities (such as more available tracks, voices and effects).

MOD files consist of "patterns" which are 64 units long. These patterns are then strung together with a sequencer which controls the order in which the patterns are played. Just as in conventional manuscript, it is possible to "repeat" a section of music; simply re-play a previously used pattern. Think of patterns as a series of computer punch cards, which can be copied and shuffled about. When finally fed into an appropriate reader Gust like a scroll is loaded into an old-time player piano), the music is played.

Creating MOD files can, therefore, occur with the help of external MIDI input devices (like a keyboard), but most MOD development is done in a "programming" fashion, with the composer laying out individual note events within the framework of the MOD system.

MOD files are readily available over the Internet; m fact, it is common for MOD musicians to "show their stuff' by posting collections of their works on the 'Net.

Summary

While there are some clear advantages to the portability offered by MOD systems, they are unlikely to supplant MIDI as a mainstream medium for musicians, because of
the inherent "geek factor" of the interface and the complexity of the MOD creation process.
However, if you're akin to computers, you may want to give it a try, if only to say you've been there, done it and bought the T-shirt.

Reference Material

A shareware program to create, edit and play MOD files, and later
extended format files based on
the MOD standard (S3M, XM, etc.)

ARCHIE: fl206.zip