It's unclear what kind of noise the downstairs tenant is complaining about.

Absolutely grinds my gears. 

The source of the noise is simply opening/closing the door and footsteps.

I do believe the guy causing the trouble is fearful of the noise and I doubt he has talked to more than a handful of others.

Now if you had a month to month tenant who "broke all the rules" (excessive noise/unreasonably disturbing the neighbors etc etc), you are within your rights to mutually resolve this with said abusive tenant using some of the pointers I outlined earlier.  

Basically the clause reads as follows:1.DISTURBANCE, SMOKING, NOISE, ILLEGAL USE: Neither the LESSEE nor his family, friends, relatives, invitees, visitors, agents or servants shall make, permit or suffer any disturbing noises or vibrations by means of a human voice, radio, phonograph, stereo, television, piano or other musical instrument or other device or form of technology of any description within the building or Premises, nor commit or permit any nuisance to exist thereon, nor cause damage to the building or Premises, nor create or permit any substantial interference with the rights, comfort, safety or enjoyment of the LESSOR or other occupants of the same or any other apartment in the building, nor make any use whatsoever thereof than as and for a private residence.

Road noise?

If the neighbor was complaining about the noise that the dog, that the tenant shouldn't have had, was making, the landlord had the right to look into this issue.

On my current path of grinding away a life at my 9-5 job I could work till I'm 45, sell my rentals, and live off my investments.

I hadn't been aware that there are power tools big enough that they require 220.If tenant installs the power, he must use a licensed electrician and get a building permit and building inspection.Here is an issue to consider: a power tool big enough to use 220 is likely to make a lot of noise.