35. Editing Graphs

Figure 35.1
Click on thumbnail for full size image.

Figure 35.1 shows the facility for editing Graphs on the database. In this case, a four-segment Graph piano2secs which was used earlier (see page 7) is shown.

It can take a fair amount of experimenting with numbers in the table to get the result you want. The Connected segments radio-button field often helps by getting the various segments of the Graph following on from each other: with this set to Yes, the starting y-coordinate of each segment is the last y-coordinate of the previous segment.

This Graph has a y-axis which is both positive and negative; if a y-axis limit lo value of 0 (zero) were entered, the Graph would have a positive y-axis only.

Gray or dark areas in the table are read-only cells; in other words, you cannot edit these.

For the mathematically minded, here are the equations for the various graph segment types:

• Linear y = Gradient × x + Intercept
• Sinusoidal y = Amplitude × sin(x × Frequency) + Gradient × x + Intercept
• Cosinusoidal y = Amplitude × cos(x × Frequency) + Gradient × x + Intercept
• Exp growth/decay y = Amplitude × exp(x × GrowthDecay) + Gradient × x + Intercept
• Sin growth/decay y = Amplitude × sin(x × Frequency) × exp(x × GrowthDecay) + Gradient × x + Intercept
• Cos growth/decay y = Amplitude × cos(x × Frequency) × exp(x × GrowthDecay) + Gradient × x + Intercept
• Square root y = Amplitude × sqrt(x × GrowthDecay) + Gradient × x + Intercept
• Cube root y = Amplitude × cbrt(x × GrowthDecay) + Gradient × x + Intercept
• Power y = Amplitude × pow(x × GrowthDecay, Exponent) + Gradient × x + Intercept
• Geometric sequence y = Amplitude × pow(CommonRatio, x × GrowthDecay) + Gradient × x + Intercept

The last four Graph segment types were introduced with version 3.2.0 of the software. Geometric sequence was introduced as a Graph segment type primarily for designing Harmonic instruments, but it may prove useful in other contexts.

The following tips may prove useful:

• You can edit values in the Gradient column to affect the orientation of a Graph segment.
• You can edit values in the Intercept column to move a Graph segment up or down.
• You can set a negative Amplitude value to invert a Graph segment.