In Sound Forge 15 we can select a waveform region and send that via ARA to external tools, edit that there, and send the edit back to Sound Forge.

But there is a small gotcha in the implementation that may puzzle people when using multiple ARA tools.

Sound Forge puts the ARA tool in the FX Plug-in Chain as the first member.

If you call a different ARA tool, Sound Forge does not replace the old member in the Plug-in Chain, so the user has to remove it before using the other ARA tools.

For example, if I edit a part of a waveform selecting the menu 'Edit in SpektraLayers (ARA)...' and later select 'Edit in Melodyne (ARA)...', on the second edit, SpektraLayers is called, not Melodyne. Removing the entry in the Plug-in Chain will fix the issue.