3 Rules to remember

1. Any Vibration does not = Vibration Training
2. Light Vibration = Therapy
3. Heavy Vibration = Training

The Blacklist

Vibration Training machines, 1 or 2 motors?

Physics is normally quite boring for the average person, but I promise to make this relatively short and interesting. Who knows you may even find yourself repeating this to other people.
  Ok to understand the basic physics behind creating a clean powerful vibration I am going to take you to the beach. What has that got to do with Vibration Training you say. Well actually most of the basic rules surrounding vibration can be observed at the beach. We are after all dealing with waves of energy.
Now there are 3 basic wave patterns.....
(1) Single Fq ......
This can be thought of a just a single wave traveling across the ocean in the form of a swell. It is often not known that multiple swells traveling at different speeds are moving across the ocean at any one time.
(2) Constructive Interference ..... 
This is where two waves roll over the top of each other in perfect unison, creating one larger and more powerful wave. On a beach you can see this in the form of a "surfers wave". Locals will even know if this is going to be every 5th or 7th wave depending on the beaches "math's"
(3)  Destructive Interference .......
On a beach this can be seen in the form of a rip, it is essentially a "dead spot" where the waves come from different angles and appear to cancel each other out. I say appear because this is not the case. As we all know energy can not be created or destroyed, so where does it go if not into the formation of a wave ?  The energy is in fact forced below the waters surface and it becomes turbulent like a washing machine. An important point to envisage when thinking about the destructive forces of waves. 

So how does this equate to a Vibration Training machine......... ?
A machine using a single motor is just a single Fq .  Easy to design, produce and understand. It is the simplest equation to have to deal with, as you are not dealing with multiple sources of energy.  It is also cheaper to build. But of course this comes at a cost, less lineal direction and clean vibration.
Using 2 motors is preferred by most companies only because it allows the chance for a "constructive interference" to be produced. But if this is done wrong, the 2 motors create a "destructive interference"  and causes all kinds of problems. These are some of the kinds of problems it can cause.....
(1) Overheating motors  ( like bending a steel rod in half, the bend gets very hot, this release of energy is enough to create a lot of heat, enough to cook a motor or expend its bearings and chew them up )
(2) Cracked steel  ( that washing machine analogy was not a joke, and it can actually break up the structural integrity of the steel )
(3) Unbalanced vibration  (  this is where the machine makes a kind of whirr-whirr noise, it means the motors are running at different speeds. They will match speeds for a second and go quite, then go back out of sync and make a deep whirring noise  )
Note: Companies like Vibro-Gym spent a fortune on creating an electronics system to keep the motors in sync for this very reason, and anyone who has used an older Pro unit of theirs will attest to the fact they can go unbalanced on occasion. Especially if a larger person stood on the machine lop-sided. Power Plates used to go unbalanced with no-one on them ??
(4) Excess noise   Basically the reverberation can ring the machine like a bell.  This kind of noise will almost be deafening and can drive you crazy, even if it does not seem very loud.
(5)  Dead spots on the machine  This manifests itself in areas where there seems to be almost no vibration. Funny enough this is where the steel is most likely to crack. Just like that rip on the beach, it is all very deceptive.
These issues become expediential the more power you want to produce, and with it room for error almost disappears. For this reason I believe most companies will keep using small motors or in some cases only 1 large motor. The consequences of "pretending" to understand the physics could end up being a warranty trap the company may not survive.