Ok - so I know this is most likely the oohed cooling fan (yay) - but how do I isolate which fan is causing the noise? Is there a procedure that lets you spin up the fans individually to max RPM or anything?
Thx
This is for certain operations/layers necessary and normal.. fast cooling. With the H2C there is a whole new noise composition running… comparing to my former X1C. 
I don’t thin thats what it is - the noise has been getting progressively worse over the past few days. When I spin the internal toolhead fan up with compressed air, you can hear it making a noise as it winds up and down.
I hope you aren’t just spinning the fans with compressed air. I can be a web like filament stuck inside ?