I just purchased a Wahoo Kickr Core and after getting my bike on it I noticed a very loud noise that seems to come from the cassette area… I have no clue if it is related to the chain or cassette or the trainer itself.
I had been on a Kickr before with this same bike and you didnt feel the sprockets grinding so much.
You are referring to the “hummm” in the background, right?
Check the opposite side, where the flywheel is: are the stickers all very well attached to the flywheel? It happened to me that a couple of them were lifting up, causing noise (air friction :S). Removed them and it went back to be super quiet.