While it may sound conceptually similar to other S9x effects, I am afraid this feature would be about as low-level as it can get: It would require new mixer functions to be added, because right now (like in practically any other sample player), the left sample channel is always mixed into the left mix channel and the right sample channel is always mixed into the right mix channel. There is no way to swap channels or play one sample channel in both mix channels.

I was afraid of that. Well, it was worth a shot. I'm sure some other hacky solution could be found using the sample data itself, but at that point, why bother, right?
EDIT: Would probably be equally low level, too...

I don't think I can see any sensible, maintainable way to achieve this without explicitly upgrading the mixer. It might be more feasible to find a VST plugin that can achieve these things. Stereo swap should be simple to find, at the very least.

Fair enough. I do hope something comes up, but it does sound fairly difficult so my hopes are not high. I only asked because I typically work exclusively with DirectX plugins so that my modules can be played back via libopenmpt.

I guess it would be possible to implement it as a built-in plugin still - maybe a general stereo processing tool that allows to do mid-side editing, stereo swapping, mono conversion, etc...

Here's a potential list of features for such a stereo processing tool, some of which I have wanted for a while now, some of which are from this feature request:

• Amplify Mid/Side or L/R independently
• Change Stereo width (with multiple frequency bands)
• Swap stereo channels (could be part of stereo width feature)
• Only play left / right / mid / side
• Convert L/R to Mid/Side and vice versa
• Pan & Gain