So the deaf have something to complain about too.
It is NOT the electric motor creating that sound, it is the suction pump that is driven by the motor that is creating that sound while creating the partial vacuum that sucks in the dirt. If you have an upright vacuum cleaner, the beater brushes also make quite a bit of noise when you have them turned on when doing carpets.
Dogs have sensitive ears, so the loud noise hurts their ears causing them to bark at the source. like the dog said so.
The noise of a vacuum may appear very soothing to you.
Noise that household appliances generate
geological noise electronic noise vacuum cleaner gas lamp uncontrolled ground noise
The cause could be your muffler. Mine has a hole in it and when I accelerate it roars, kind of like a vacuum.
One answer in not an inexpensive but you can purchase a central vacuum, install it in the garage and place your hose ports in your closets. the only noise you will here is the suction.
A whistling noise indicates a vacuum leak.
It is more than likely afraid of the vacuum because it knows that the vacuum makes noise and that the vacuum could turn back on.
You may have a brake booster that is leaking. The diaphragm may be busted. You will need to remove the brake booster vacuum hose and do a vacuum bleed down test. If the booster will not hold vacuum it needs replacing.
Partition Noise, which occurs in vacuum tubes, optical fibers etc.
When lighting strikes it causes a cavity or vacuum in the air the loud noise is caused by the vacuum collapsing. as an example popping a plastic bag cause the same effect.