Lesson 4

Table of Contents

Adding an LFO

Low Frequency Oscillators—LFOs—are another way to manipulate properties of a synth. Don’t misunderstand the name as something to do with low frequency sound generation. An LFO is simply another way to modify property settings over the course of time in a way similar to how an Envelope works. The difference is that an LFO repeats a value change over and over again in a pattern at a specified frequency.

You’ll explore the use of an LFO in conjunction with the Boss-A-Melody track. This track has longer sustained notes, and you’ll use an LFO to create a vibrato sound that can be heard on those longer notes.

For the Boss-A-Melody Music Track, you’re going to use a slightly different synthesizer sound. This means that you need to create another Sound SFX object with a Synth One source. Since the sound to be used with the track will be similar, you can use the Arpeggio Synth Sound SFX object you’ve already created as a template.

  1. Right-click the Arpeggio Synth Sound SFX object and choose Copy.

  2. In the Actor-Mixer Hierarchy right-click the Music Work Unit and choose Paste.

  3. Rename the newly created object Melody Synth.

  4. In the Interactive Music Hierarchy select the Boss-A-Melody Music Track and click the MIDI tab in the Property Editor.

  5. In the MIDI Target group, click the Override parent check box. Then drag the Melody Synth Sound SFX object to the MIDI Target property in the Property Editor.

  6. Play the Boss-A Music Segment. You hear the new synth line play along with the rest of the music. Because the target for this track is a Sound SFX object that was copied from the Arpeggio Sound SFX object, the Melody and Arpeggio sounds are identical. To make the parts more distinguishable, you need to modify the Melody synthesizers sound.

  7. Select the Melody Synth Sound SFX object and double-click the Wwise Synth One icon in the Contents Editor. The Wwise Synth One Source Editor opens. Select the Effect Settings tab to view its Synth One properties.

    You’ll make a slight modification to the sound to differentiate from the Boss Synth 1 sound.

  8. Set the FM property to 0 and play the Boss A Music Segment.

    You hear the track play and the Melody line is a lot more mellow sounding.

    Now you’re ready to add a bit of vibrato to the sound. Vibrato is a repeating, rapid rise and fall in pitch of a sound, so assigning an LFO to the pitch of a synthesizer works perfectly for this application.

  9. In the Source Editor, click the RTPC tab.

    You see the default Envelope assignment like you saw in the last exercise. In this same area, you can add an LFO.

  10. Click the [>>] selector on the second line and choose Osc 1 Transpose.

  11. Click the [>>] selector menu under the X Axis column and choose LFO > New.

  12. Name the LFO Synth Vibrato.

    [Tip]

    This creates a Modulators ShareSet that will not only be used for this synthesizer, but could also be applied to other synthesizers should you want the same vibrato effect with other synthesizers you might configure.

    The RTPC graph displays a pink line representing the intensity the LFO will have on the transposition.

    To better understand what the line represents, and to display the scale used on the graph's Y axis, you should focus the graph on the second row's properties.

  13. Click the second row in the editor.

    The graph is now focused only on the Vibrato LFO modulation you created. Like you learned with the Envelope in the last exercise, this RTPC curve represents the degree of intensity that the LFO will have on the selected property, but the graph doesn’t represent the LFO itself. You can see that the vertical axis represents a change in pitch expressed as cents, so currently there would be no pitch change regardless of any changes you may make to the LFO properties. To change this you’ll want to adjust the point on the right side, but for a vibrato effect, you don’t want the pitch change to be too much. The current scale is displaying the potential for many octaves of pitch change, which would be far too much for a subtle vibrato effect.

  14. Zoom in on the vertical axis so you can see roughly 200 cents of change on the graph.

    Now you need to drag the right control point up to represent the maximum amount of pitch change the LFO could have on the Osc1 Transpose’s pitch.

  15. Drag the control point on the right side up until you see a value of 150 in the Y axis property.

    Now, whatever changes you make to the LFO properties found in the lower-right pane, the greatest effect it could have is an offset of 150 cents to the transposition property.

  16. Set the Frequency to 6.

  17. Play the Music Track to hear the vibrato effect on the melody line.


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