Strange sound Octoprint 13.11

My install is making my printer (Anycubic Mega-S) sound like it has no bearings every so often. It's not constant but enough to be an issue. It doesn't happen printing from the SD card otherwise I'd think hardware issue. I've gone through the tools and done everything I've seen to do. It sounds like maybe the print is being performed at a rate that is maybe creating a harmonic in the hotend carriage. Anyone see this before?

Thanks from a newbee :slight_smile:

I have three fans on one of my rigs and a single fan on another. Two of these sometimes make an angry sound upon startup (pretty loud actually) and I've found that if I just grit my teeth and wait the sound goes away when it warms up a bit. If these were production printers then I'd replace the offending fans.

Come to think of it, I've changed three fans in my Ethereum rig already and it's only maybe three years old.