next up previous
Next: Patterns Up: Reference Manaul Previous: Running MMA

Subsections


Tracks and Channels

This chapter discusses MMA tracks and MIDI channels. If you are reading this manual for the first time you might find some parts confusing. If you do just skip ahead--you can run MMA without knowing many of these details.

MMA Tracks

To create your accompaniment tracks, MMA divides output into several internal tracks. There are a total of 8 different types of tracks, and an unlimited number of sub-tracks.

When MMA is initialized there are no tracks assigned; however, as your library and song files are processed various tracks will be created Each created a unique name. The track types are discussed later in this chapter, but for now they are Bass, Chord, Walk, Drum, Arpeggio, Scale, Melody and Solo.

All tracks are named by appending a ``-'' and``name'' to the type-name. This makes it very easy to remember the names, without any complicated rules. So, drum tracks can have names ``Drum-1'', ``Drum-Loud'' or even ``Drum-a-long-name''. The other tracks follow the same rule.

In addition to the hyphenated names described above, you can also name a track using the type-name. So, ``DRUM'' is a valid drum track name. In our library files we usually use the type-name to describe patterns.

All track names are case insensitive. This means that the names ``Chord-Sus'', ``CHORD-SUS'' and ``CHORD-sus'' all refer to the same track.

If you want to see the names defined in a song, just run MMA on the file with the ``-c'' command line option.

Track Channels

MIDI defines 16 distinct channels numbered 1 to 16.3.1 There is nothing which says that ``chording'' should be sent to a specific channel, but the drum channel should always be channel 10.3.2

For MMA to produce any output, a MIDI channel must be assigned to a track. During initialization all of the DRUM tracks are assigned to special MIDI channel 10. As musical data is created other MIDI channels are assigned to various tracks as needed.

Channels are assigned from 16 down to 1. This means that the lower numbered channels will most likely not be used, and will be available for other programs or as a ``keyboard'' track on your synth.

In most cases this will work out just fine. However, there are a number of methods you can use to set the channels ``manually.'' You might want to read the sections on Channel ([*]), ChShare ([*]), On ([*]), and Off ([*]).

Why bother with all these channels? It would be much easier to put all the information onto one channel, but this would not permit you to set special effects (like Portamento or Pan) for a specific track. It would also mean that all your tracks would need to use the same instrumentation.

Track Descriptions

You might want to come back to this section after reading more of the manual. But, somewhere we need to describe the different track types, and why they exist.

Musical accompaniment comes in a combination of the following:

Of course, this leaves the melody ... but that is up to you, not MMA... but, if you suspect that some power is missing here, read the brief description of Solo and Melody tracks ([*]) and the complete ``Solo and Melody Tracks'' chapter ([*]).

MMA comes with several types of tracks, each designed to fill different accompaniment roles. However, it's quite possible to use a track for different roles than originally envisioned. For example, the bass track can be used to generate a single, sustained treble note--or, by enabling Harmony multiple notes.

The following sections describe the tracks and give a few suggestions on their uses.

Drum

Drums are the first thing we usually think about when we hear the word ``accompaniment''. All MMA drum tracks share MIDI channel 10, which is a GM MIDI convention. Drum tracks play single notes determined by the Tone setting for a particular sequence.

Chord

If you are familiar with the sound of guitar strumming, then you're familiar with the sound of a chord. MMA chord tracks play a number of notes, all at the same time. The volume of the notes (and the number of notes) and the rhythm is determined by pattern definitions. The instrument used for the chord is determined by the Voice setting for a sequence.

Arpeggio

In musical terms an arpeggio3.3 is the notes of a chord played one at a time. MMA arpeggio tracks take the current chord and, in accordance to the current pattern, play single notes from the chord. The choice of which note to play is mostly decided by MMA. You can help it along with the Direction modifier.

We use Arpeggio tracks quite often to highlight rhythms. Using the RSkip directive produces broken arpeggios.

Using different note length values in patterns helps to make interesting accompaniments.

Scale

Another embellishment. When MMA plays a scale, it first determines the current chord. Its scales are started on the first note of the chord (if the chord is a C7, the scale will be a C scale). Currently, three types of scales are supported: major, natural minor and chromatic.

The major scale is selected for all chords which are not of a minor flavor, or if the ScaleType is set to Major.

The natural minor scale is selected for all ``minor'' chords. This includes chords such as ``Cm7'', ``G#m13'', etc. If the ScaleType is set to Minor this scale is always used.

If the ScaleType is set to Chromatic, then a chromatic scale is used.

MMA plays successive notes of a scale. The timing and length of the notes is determined by the current pattern. Depending on the Direction setting, the notes are played up, down or up and down the scale.

Bass

Bass tracks are designed to play single notes for a chord for standard bass patterns. The note to be played, as well as its timing, is determined by the pattern definition. The pattern defines which note from the current chord to play. For example, a standard bass pattern might alternate the playing of the root and fifth notes of a scale or chord. You could also use Bass tracks to play single, sustained treble notes.

Walk

The Walk tracks are designed to imitate ``walking bass'' lines. Traditionally, they are played on bass instruments like the upright bass, bass guitar or tuba.

A Walk track uses a pattern to define the note timing and volume. Which note is played is determined from the current chord and a simplistic algorithm. There is no user control over the note selection.


Solo and Melody

Solo and Melody tracks are used for arbitary note data. Most likely, this is a melody or counter-melody ...but these tracks can also be used to create interesting ending, introductions or transitions.

Silencing a Track

There a number of ways to silence a track:

Please refer to the appropiate sections on this manual for further details.



Footnotes

... 16.3.1
We use the values 1 to 16 in this document. Internally they are stored as values 0 to 15.
... 10.3.2
This is not a MIDI rule, but a convention established in the GM (General MIDI) standard. If you want to find out more about this, there are lots of books on MIDI available.
...arpeggio3.3
The term is derived from the Italian ``to play like a harp''.

next up previous
Next: Patterns Up: Reference Manaul Previous: Running MMA
Bob 2004-12-02