Pattern Length and Chord Rhythm
Now let's discuss chord rhythm, pattern length, and how DirectMusic chooses which pattern is appropriate to play a given set of chords. So far, every Style that we have dealt with had only one pattern, but it is often better to have several patterns to add variety. One chord change every measure with the same musical motifs repeatedly can get tiresome. You can compose separate patterns for each level of chord activity. By default, DirectMusic picks the longest pattern that fits the chord rhythm in the Segment. This default behavior only holds true if you have a Groove Track with a groove level specified. Adding a Groove Track will not hurt your content if you do not plan to use grooves. Just put any number in the first measure. For an example, look at the bookmark AdvancedTechniques. The Style has two patterns. One is one measure long, and the other is four. What really matters is the chord rhythm. Go to the properties page of the pattern 4Bar. At the bottom is the chord rhythm section. You can click the Set button to change the setting. After adjusting the setting, you can then click the boxes to put an x in every place where there should be a chord change. The four-measure pattern is chosen every time that there is no chord change for four bars because the pattern follows only one chord for four measures. If you put an x at the beginning of every measure, the 4Bar pattern always plays because it is the longest pattern with the correct chord rhythm in all cases.
There are two variations in 4Bar. One variation is a single chord, but the other variation moves every two beats. Patterns with only one chord change are a good way to take some liberty with the chords in your patterns. You can have different chord rhythms in every variation. Faster, syncopated, and less regular chord rhythms are sometimes better written out exactly without being subject to Chord Track's control. Chord rhythm variability is very easy with this pattern, since there is only one part and there is no need to do variation locking to keep the harmonies together.
You can still build inherent chord progressions into different variations if you have multiple parts. All you need to do is take advantage of locking variations. To get this setup to work, you need to make sure that the ChordMap can play for a longer period of time with only one chord. In this example's ChordMap (shown in Figure 6-10), you will notice a connection that has been drawn from the first signpost directly to the second target signpost. If there were no connecting chords, this would not be necessary, but since there are connection chords, DirectMusic will only take paths that are specified when moving between these two signposts.
Figure 6-10: Randomly bypassing connecting chords.
More on Variation Choices: The Mother of All Windows
To get to the Variation Choices screen, press the ? button next to the variation numbers in your pattern. Figure 6-11 shows only half of the window. The full window displays a row for all 32 variations in a part. Each row tells what types of chords that variation can play on. Pushed buttons are situations that are legal and unpushed buttons are situations that are forbidden by the content creator. Note that something will always play, so if a chord is selected and there are no variations that are allowed to play over that chord, an illegal variation will be selected at random.
Figure 6-11: Variation Choices window.
Figure 6-11 is the string part's variation choices in the AdvancedTechniques example. All variations besides 1 through 6 are disabled, so they appear almost in black. Variation 1 hangs on the fourth scale degree, so it does not sound very good over major chords because of the half-step difference with the third. As a result, all of the major triads are disabled for that variation. The iv chord is disabled since variation 1 didn't sound pleasing over that chord to the author. Variation 2 hangs on the second scale degree, so it does not sound very good over the diminished chords represented in italics. There are only two diminished chords in the ChordMap, so those are the only two disabled. Variations 3 and 4 sounded good to the author with any chord, so every button is pushed in their rows. Variations 5 and 6 are reserved for the I chord, since they are whole notes bringing resolution.
The other buttons are not used in this example, but they can be very useful for creating more interesting harmonies. Before these other buttons are explained, it must be made clear that the scale degrees represented by the Roman numerals depend on the Chord Track in the Segment. This, however, does not mean that you are limited to standard major and minor scales. A key of F with five flats would result in F Phrygian or F, Gb, Ab, Bb, C, Db, Eb, F. In that case, ii means Gb minor and VII means Eb major.
The Root section tells whether or not variations can be played on chords built off scale degrees that have been raised, lowered, or unchanged. In the F Phrygian example, unchecking S would mean that the variation could not play on a chord based on F, Gb, Ab, Bb, C, Db, or Eb. If # was unchecked, chords based on F#,G, A, B, C#, D, and E would become illegal.
In the Type section, "tri" means triads, "6,7" means chords with sixths or sevenths added, and "Com" means complex chords. The Dest area specifies a chord's destination.
Before we wrap it up, there is one more trick that you should know about when dealing with ChordMaps. If you ever need to transpose a set of chords, there is a trick to doing it without having to do it chord by chord. Create a dummy ChordMap that you do not plan to use. Copy your chords into that ChordMap, and then change the key of the clipboard ChordMap, transposing all of the chords that you just pasted in. Select those chords, paste them into the ChordMap that you are actually using, and you have a set of transposed chords.
Congratulations! You have just completed an in-depth tutorial on one of the most intimidating and powerful parts of DirectMusic. We wish you luck in becoming comfortable and at ease with these revolutionary concepts. There are so many things to explore in the world of DirectMusic harmony, and there were so few pioneers at the time of publication. We hope that this chapter has given you the knowledge and understanding necessary to dig in and write some great interactive music.