WaveTables Quick Start

WaveTables store periodic wave data in lookup tables and provide a way to perform wavetable synthesis and sampling in MetaSounds.

This guide teaches you how to create a MetaSound powered by two WaveTables with different Sample Modes.

• Fixed Resolution - Enforces uniform resolution of all WaveTables in the bank. This mode supports lockstep mixing, interpolating, and spatializing, which is useful for oscillating or enveloping.
• Fixed Sample Rate - Enforces uniform sample rate for all WaveTables in the bank. This mode supports discrete audio playback at a shared speed, which is helpful for sampling and granulating.

Create the Fixed Resolution WaveTable Bank

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To create the Fixed Resolution WaveTable Bank:

1. In the Content Browser, click the Add button.
2. Select Audio > WaveTable > WaveTable Bank.
3. Name the WaveTable Bank WTB_FixedResolution.
4. Double-click the WaveTable Bank to open the WaveTable Bank Editor.
5. In the Details panel:
   1. Disable Bipolar.
   2. Click the Add Element (+) button for Entries twice.
   3. Expand Index [0] and set Curve Type to Linear (Ramp Out).
   4. Expand Index [1] and set Curve Type to Linear (Ramp In).
6. Save the WaveTable Bank.
7. Close the WaveTable Bank Editor.

Create the Fixed Sample Rate WaveTable Bank

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To create the Fixed Sample Rate WaveTable Bank:

1. In the Content Browser, click the Add button.
2. Select Audio > WaveTable > WaveTable Bank.
3. Name the WaveTable Bank WTB_FixedSampleRate.
4. Double-click the WaveTable Bank to open the WaveTable Bank Editor.
5. In the Details panel:
   1. Click the Add Element (+) button for Entries twice.
   2. Expand Index [0]:
      1. Set Curve Type to Sine (360 deg)
      2. Set Duration (Sec) to 0.5.
   3. Expand Index [1]:
      1. Set Curve Type to Sine (360 deg).
      2. Set Duration (Sec) to 1.0.
6. Save the WaveTable Bank.
7. Close the WaveTable Bank Editor.

Create the MetaSound Source

Click image for full size.

Construct a MetaSound that uses the WaveTable Banks for generating and enveloping. Follow the steps below to build a MetaSound with the graph above.

1. In the Content Browser, click the Add button.
2. Select Audio > MetaSound Source.
3. Name the new MetaSound MSS_WaveTableDemo.
4. Double-click the MetaSound to open the MetaSound Editor.
5. In the Interfaces panel, click the Remove (Trash Bin) button next to the UE.Source.OneShot Interface entry. This removes the On Finished Output node, which isn't used on looping sounds.

Build the Generator Section

1. Find the On Play Input node in the graph and drag off of the pin into an empty space. Enter "Trigger Repeat" into the node search to create a connected node. You can move the node around the graph by dragging it.
2. On the Trigger Repeat node:
   1. Set Period to 1.0.
   2. Drag off the RepeatOut pin and create a Trigger Counter node.
3. On the Trigger Counter node:
   1. Set Reset Count to 2.0.
   2. Drag off the On Trigger pin and create a WaveTable Player node.
   3. Connect the Count pin to the Index pin of the WaveTable Player node.
4. On the WaveTable Player node:
   1. Click the Bank dropdown and set it to WTB_FixedSampleRate.
   2. Set Pitch Shift to 440.0.
   3. Enable Loop.

Build the Envelope Section

1. Right-click in an empty space and create a Get WaveTable From Bank node.
2. On the Get WaveTable From Bank node:
   1. Click the Bank dropdown and set it to WTB_FixedResolution.
   2. Drag off the TableIndex pin and select Promote to Graph Input. This creates a Float Input node named TableIndex.
   3. Drag off the Out pin and create a WaveTable Envelope node.
3. On the WaveTable Envelope node:
   1. Drag off the On Play pin and create a Get On Play node.
   2. Click the down arrow at the bottom of the node to expand the pin list.
   3. Set Mode to Loop.

Connect the Outputs

1. Right-click in an empty space and create a Mono Mixer (2) node.
2. On the Mono Mixer (2) node:
   1. Connect the In 0 pin to the Mono Out pin of the WaveTable Player node.
   2. Connect the Gain 0 (Lin) pin to the Out pin of the WaveTable Envelope node.
   3. Connect the Out pin to the Out Mono Output node.
3. Save the MetaSound.

Test the MetaSound

Click the Play button on the MetaSound Editor Toolbar to play the MetaSound. You can adjust the TableIndex graph input value by clicking the Input Widget (Dial) on the node and dragging up or down.

The WaveTables in WTB_FixedSampleRate alternate playback every second. The gain is controlled by a WaveTable from WTB_FixedResolution, which is selected by the TableIndex graph input. TableIndex values between 0 and 1 produce a blend between the WaveTables in the bank.

Own Your Own!

Now that you've finished this Quick Start, consider taking this project further. Below are some suggestions you can explore on your own.

• Build a MetaSound with the WaveTable nodes not used in this guide, such as the WaveTable Oscillator node and Evaluate WaveTable node. For more information on WaveTable nodes, see MetaSounds Reference Guide.
• Customize your WaveTable curves by setting the Curve Type to Custom. See Curve Editor for more information about the toolbar and editing curves.
• Import audio files as a WaveTable by setting the Curve Type to File and the Wave Table Settings > File Path.