Hey my loopback audio is now working correctly after the latest obs version.
Ditto. Took a little figuring out on my part, though, as it was a little different going from Reason to OBS.
In Reason: Edit > Preferences > Audio > kept audio card driver to ASIO MiniFuse ASIO Driver.
(Still under Audio tab) Active output channels > Channels > LOOPBACK Left/Right.
In OBS: Add an Audio Input Capture > Device > LOOPBACK Left/Right > OK. Click the more button for the channel > Advanced Audio Properties > under Audio Monitoring > Monitor and Output. Done.
ON EDIT: I should note that in Reason, under the active output channels, only LOOPBACK should be enabled; enabling the main outputs makes the whole thing go kablooey.