what is the right action to slap ??
low action or high action ???
I know everyone have their own style and likely, but I want to know your opinions

Low Action of course!!
I always try to have my bass at the lowest action posible.
Of course, only high end basses can give you a really low action.
:( I dont have a really high end bass.

Low is the way to go, bro' :D

No use to make life/playing harder than it already is...

A great topic for the "Setup" forum....

Lower action is usually better, but keep in mind that you don't want to slap all the time. The best is to have a setup that lets you have a good slap tone as well as a good pick/pizzicato tone...

Will C.:cool:

yes I play finger style but I slap alot too
I'd tried to lower the action as low as I could, it doesn't rattle or buzz when I play with my fingers and it feels good
but the thing is, when I slap the E and A string , they dont sound good. No sustain and no punch.
so what happen ??

You probably have it too low. If you don't have room to strike the string without it hitting the fretboard you'll limit the ease of working with a wider range of dynamics... "unless" you really work on developing a light touch.