WudfCoInstaller - new audio noise?

Not sure sonar has anything to do with this, but the timing is suspiciously coincidental:  have never had audio problems before, but after installing Dorchester I now get a hum from the headphones; goes higher or lower depending on windows open.  
 
Something (Dorchester?) used "WudfCoInstaller" and created a log file, including many of these error messages:  "AudMig: No audio endpoint migration settings found"  and "removing existing settings in preparation for setting new ones".   

I'm leaning toward coincidence.   Tried rolling back the update, still had the noise.   Messed with cables and reseated audio and video and it seems much less, though still there.   Thanks for the help.