Thanks for the plugin - it is doing the whole capture side of a 3rd-order ambisonics project for me, 16 discrete channels from REAPER into OBS as four tracks of four. Posting the one step that took me a while to find, in case it saves someone the search.
My setup: Windows 11, OBS Studio 32.2.1, atkAudio 0.33.1, REAPER 7.78 over ReaRoute.
An
OBS Output node is stereo by default, and nothing in the OBS source's Properties changes that. The control is inside the PluginHost2 graph: right-click
the node itself (not a port), choose
Configure Audio I/O, and set the
Input Configuration's Channel Layout - I used
Discrete #4. Repeat for every node; each one left at stereo quietly costs two channels.
View attachment 120768
right-clicking the node itself, not a port
View attachment 120769
Input Configuration has a numbered bus; Output Configuration below it has only + and -, no bus. Stereo is ticked, Discrete #4 highlighted.
Only the Input Configuration matters. The dialog draws an Output Configuration too, but there is no bus under it, which matches ObsOutput.h declaring an input bus and no output bus.
Why it is worth knowing: with nodes at stereo and OBS offering six tracks, the ceiling is 6 x 2 = 12 channels, so 16 is simply unreachable however many nodes you add. And there is a hard per-source ceiling of 8: processBlock casts the input-bus count to OBS's speaker_layout, and anything above MAX_AUDIO_CHANNELS becomes SPEAKERS_UNKNOWN, which OBS documents as falling back to stereo. So the dropdown will cheerfully offer 7th Order Ambisonics, but nothing wider than 7.1 (8 channels) can actually cross into an OBS source. In my project I only needed 4 per node to match one OBS track, but that ceiling is worth knowing if you needed more. A wide bus might still be useful inside the graph itself if you are using it to host VSTs.
View attachment 120770
the finished graph, one Audio Input fanned out to four OBS Output nodes, four channels each
One question: is the stereo default deliberate, or is following the OBS track width something you would consider? Happy to open a PR adding a line about this to the README either way.
Two OBS-side gotchas that cost me time but are not yours: Settings > Audio > Channels sets the width of every track, and REAPER's engine idles when OBS takes focus unless the tracks are record-armed.
(This came out of an open-source project I run streaming 3rd-order ambisonics with 360 video - full setup instructions at
https://github.com/mormegil6/hoa-360-stream/blob/main/docs/obs-windows.md, if you're curious.)