by Lloyd Shaw
This problem is raising its head again and again , with one company being
sued in Italy for not warning its customers about issues such as the noise
and vibration that these units can create. In this case cracking a
neighbours bathroom tiles. It seems they are pleading ignorance as to the
nature of vibration , which is funny considering they sell big vibrators for
a living ?
I will go through the basic potential problems one at a time , and they can
be discussed in more depth in the blog if needed.
(a) Vibration..
Vibrations can travel through your building much further than you imagine ,
this can depend on the construction of the building and how powerful the
vibrations are being sent "downwards".
A number of things can be done to help these problems with mats , good
isolators etc... but you will always get some energy being sent into the
floor.
The science of annoying your neighbours...
A typical home unit produces 3G of force . This means the object being moved
becomes 3 times its own weight while being slung around by the vibration.
A typical home unit weights about 60kg.
So 3 x 60Kg = 180
The unit running by itself is like a 180Kg person jumping up and down on
your floor. Yes putting a mat under the person will help , some isolators
will work better , but you still have 180kg of mass jumping up and down on
your floor.
But wait folks , it gets better. How much do you weight ? Add that to the
equation once you get on top and start working out. Lets say you weight
70Kg.
3 x 70kg = 210 .
Add that the machines and you have 390kg of dynamic mass moving around in
your building , think the neighbours will feel that ?
Creating a noise 150 feet away...
These vibrations can travel silently under you and turn a wall 50 meters away
into a speaker. If fact the machine may appear very quite standing right
next to it, so being deceived at the shop is very easy.
How does this work ? Well a speaker is only a flat surface being vibrated ,
it hits the air and causes a "sound wave" to hit your eardrum , and your
"hear" the change in air pressure. Think about an old record player (
gramophone ) , it has a small needle running over little bumps , this causes
a "vibration" which is then amplified into a horn so it is loud enough to
hear.
If you are vibrating someone's wall next door you are effectively playing
your machine into their living room.
My advice , talk to the sales staff before putting one in your house , if
they do not know any of this stuff , walk away.
