Listening to one of the videos leads me to think that there may not be anything wrong with the SC and the other makes it sound not so normal.
Sounds like mine:
https://www.youtube.com/watch?v=obZlz3kMr0I
Less like mine:
https://www.youtube.com/watch?v=E3pHfwP-nn4
A few bad bearing vids:
https://www.youtube.com/watch?v=Gz4J7lfA2sk
https://www.youtube.com/watch?v=4Rif4gSMQXU
https://www.youtube.com/watch?v=IhbzZLDP0cA
I don't think the SC sounds like any of the bad bearing vids, but I also think it's a little louder than expected. Again, I've reached out to SpecialtyZ and Vortech as well to see if they have any insight into what, if anything, may be wrong with the SC unit.
If you guys have any videos for me to compare mine to, I would appreciate it!