Starting with Reaper 5.98, you can assign SpectraLayers Pro as an ARA plugin to your tracks or regions.
To assign SpectraLayers Pro to a track:
- Click the FX button of a track
- Select VST3: SpectraLayers
To assign SpectraLayers Pro to a region:
- Right-click an audio region, Item Properties…
- Click Take FX…
- Select VST3: SpectraLayers