Most ads for the fans will list the decibel range and depending on how close it will be to you, you might get an idea of the sound. I have a three speed squirrel cage fan and it is now being put on the OUTSIDE of my new studio shed.
Sounded like a jet engine to me and no I don't have a clue of the decibels with out a meter, it came used from the A/C companies squirrel cage graveyard.....
This link might help:
https://www.chem.purdue.edu/chemsafe...n/dblevels.htm