Hi Stephen,
There’s a list bannered and pinned to the top of the forum with the most common tips and suggestions, like disabling Exclusive Mode, Hardware Acceleration (in the Advanced tab) as well as all Enhancements, for all audio devices.
If you haven’t done so yet, try setting the FxSound Speakers device as the Default Device, and your desired output device as the Default Communication Device.
For troubleshooting purposes, it’s always helpful to mention which version of FxSound you are running. This is shown in the Help tab of the Settings. A “Preferred Output Device” feature was recently added to the General tab in v1.1.26.0 (the text in blue is a quick one-click link to the explanation on that), while the versions before that had an “Automatically switch to newly connected output device” feature. Make sure to check those settings as well.
You can update anytime from the Help tab, by clicking the “Check for updates” button, and you can always find the most recent update on fxsound.com.
Following the advice below, and sharing the results obtained from running the fxdiag.exe diagnostic tool through command prompt, should be useful for your issue as well: