QuiltE

I don't have the 8900 ... so am commenting re my experiences with the 6600.

I think what you are asking re your bobbin winding is that the thread is not wound on tight, and if you push against it with your finger it is mushy? .... if so, check that you have it threaded correctly from the spool thru to the bobbin before you start the wind. One time, I had a mushy ... and turned out I had missed a step for the threading. Just put the mushy bobbin onto the spool holder, and wind it onto another bobbin.

The noise in the bobbin area ... do you have the bobbin holder in place correctly? Again, I'm going with the 6600 experience, and if you take the bobbin holder out, it's very easy to put it back in wrong ... and if operated as such, you can ruin the bobbin holder very easily, and then have chain effects to the rest of the operation of the machine.

I had noticed how much quieter my 6600 was from my two previous Janomes. The 8900 promos have spoken directly about its quiet operation.

Check these things first, then as the others have suggested, be in touch with your dealer. And be sure to take advantage of the free classes to learn more about your machine, no matter how much experience you have as a sewist. Good Luck!