Setting the Chord Reference


Setting the Chord Reference

For DirectMusic to transpose a melody to a new chord, it needs to understand the relationship of the melody to its chord and scale. In our case, we base the bass line and melody off a C7 chord.

Add a Chord Track to the bass and melody Segments by right-clicking in the Segment window and selecting Add Track and Chord Track from the menus. Right-click on the first beat in the measure of the Chord Track and select Insert to insert a chord.

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Figure 5-4: We define the chord and scale reference in the Chord Properties page. Here we use a C7 chord with a C Mixolydian scale.

On the bottom piano roll, set the chord to C7. Do this by clicking on the appropriate notes on the piano roll (C2, E2, G2, and Bb2). Now adjust the scale by changing the B natural to a Bb. Repeat this process for the second part as well.

Note 

You can copy the chord from the Chord Track and paste it in the other Segment's Chord Track, rather than resetting the notes manually.



Creating a Primary Segment

Now that both of our parts reference chords and scales, we must create a chord progression for them to play over. Create a new Segment called MasterSegment.sgt, set its length to four bars, and add a Chord Track. Place a series of chords in this Chord Track for the bass and melody parts to follow by selecting bar one and pressing Insert to insert a new chord. Use the following chord progression:

  • C7> F7> G7> C7

The notes and scales for these chords are shown here:

start figure

Chord

Chord Notes

Scale


C7

C E G Bb

C D E F G A Bb

F7

F A C Eb

C D Eb F G A Bb

G7

G B E G

C D E F G A B

end figure

Figure 5-5: Adding your melody and bass line.

Add two Segment Trigger Tracks to MasterSegment.sgt. A Segment Trigger Track allows you to include another Segment inside of your Segment, which is extremely useful for organization. In your Segment Trigger Track, right-click on the first beat of the first bar and select Insert from the menu. Select your bass Segment from the drop-down box in the properties page. Now copy and paste this Segment into all four measures on the Segment. Repeat this process on the second track to include the melody as well. Play this Segment. Notice that your instrument settings vanish, and both tracks sound like a piano. To fix this, add a Band Track to the Segment, and copy the Band from your original, imported Segment file into this track.

When you are done, MasterSegment.sgt should look like this:

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Figure 5-6: Your completed master Segment.

Play the Segment and notice how the notes now transpose to follow the chord progression.



Making Our Music Cooler

Play the Segment and notice that both the bass and melody move in a linear fashion. That is, when the chord changes from C7 to F7, both lines move up a fourth in parallel. If two musicians were to play this, it is unlikely that they would move through these changes in such a strict parallel fashion. DirectMusic allows us a number of ways to specify how a given part should move through the chord changes.

Open the properties page onto the F7 chord. Notice that there are four different chord and scale levels. Use these different levels to specify alternate ways in which DirectMusic should interpret the chord. On the second level of the chord, change the chord mapping so that the top two notes of the chord are on the bottom of the chord. It should now be composed of C, Eb, F, and A, which is the second inversion of the chord. For the G7 chord, set the second chord to the second inversion as well (in this case, C, E, G, and B). Your chord should look like this:

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Figure 5-7: Setting up alternate ways for DirectMusic to interpret the G7 chord.

Now go back to your melody Segment file, right-click on an area of the pattern where no notes are found, and bring up the properties dialog. In the bottom, right-hand corner under Default Play Mode, set the chord level to Chord Level 2 so that this pattern follows the chord mappings specified in the second layer of the chord.

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Figure 5-8: Adjusting chord levels.

Play MasterSegment.sgt again. Notice that while the bass is moving linearly through the chord change, the melody now uses the inversion to determine the root note of the melody. Save your project.

In case you are lost, there is a completed version of this section of the tutorial on the companion CD located in Unit I\Chapter 5\Tutorial Part One.