Thanks again for all the replies! I did go back and check the bobbin winding, and of course I'd not done it exactly right. Re-wound two bobbins and it is MUCH better. Thanks for that idea!
I did watch the Leah Day video, and I will need to do some testing later, because I have the clacking of the dual feed foot and the feed dogs that I've been hearing, and that might explain a lot of the noise - I'm sure that dual feed foot makes a fair amount all by itself. Obviously, since she's FMQ she doesn't have any of that noise, so I will attempt to test it (notice I say attempt; I've never done FMQ before, as my old machine was a PC-8500, totally NOT for FMQ!) and see how it sounds. I did also pull out the bobbin case and re-insert it. I hadn't taken it out myself, but it might have been removed by the dealer to clean the machine (it was a classroom machine at QuiltCon, explaining the fab deal) and not properly reseated. That did seem to help some. I did some quick testing and found that the knocking wasn't happening.
I'm sure that as I use the machine more, I will come to love it. Thanks for all the suggestions, and if someone else has anything to add, I'm certainly open to suggestions!