1996 FPX DVS-32 Annoying Blower Motor Hum

I recently installed a c.1996 Fireplace Extraordinaire (Travis) DVS32 direct vent insert. It works fine but there's a feint hum produced by the blower motor. It's not all THAT loud, but it is driving me crazy, especially when the fan is on its lowerst setting and I am sitting next to the unit. The noise is not really noticeable on higher fan speeds due to airflow noise or, when seated ~8 ft away, just to give some idea.

This is my first experience with a fireplace insert, so I have no frame of reference to compare the noise level to. What amount of hum is considered normal? Is the noise coming from the fan or the rheostat (I can't tell which it may be). Is there a way to reduce or eliminate the hum?

Any advice appreciated.

Sounds like a lot of fans I have seen. Often times on low the motor humming is more annoying than the air whoosing when you run it on high. Best solution is just don't run the blower