Taken from another thread:::
"Other than adding something inline to reduce the voltage/power coming in to the shaker, changing the size of the weights seems like the only other way since I don't see an option in the adjustment menus.

Maybe I'll try putting some rubber under the feet to absorb some of the shaking."

I would be surprised if someone doesn't make a shaker reduce kit or something along those lines. Supposedly in some of the newer sterns with shakers it can be done via the menu / settings... But I don't think you can do it that way on JP.

I agree, I put a layer of foam rubber under the shaker in my JP.

If possible, move one of the weights 90 degrees. Normally they'd point opposite each other. Put them at a right angle and it should reduce the violent shake for a nice rumble.

Agree. Not sure if JP shaker is like RS but I moved mine 90 degrees and its perfect now.

I read other threads of some sort of set screw that was adjustable...

i bet the females like it