Most fans have a secondary hum aside from the normal wooshing sound of the fan blades. What can be done to get rid of hum? Changing speed only makes it louder or subdued. This is not my exact Lasko fan These are the 20 in window kind. Before mentioning cleaning this is a problem with a brand new one I just took out of the box.
I thought it might be some small modification of the blades (?)