First of all-you can`t exactly do an open strin vibrato, but you can do a fourth finger vibrato, considering fourth finger is meant to match the string next to it. [Eg, fourth finger on the d string is supposed to match A. Fourth finger on the G string is supposed to math G. Ect]

When you first begin the vibrato you end up shaking your instrument [I did that as a biginner] but sooner or later you get the hang of it,

Open string vibrato means no fingers. So technically, you CAN`T vibrato on open strings.

Your "fake" vibrato-ing can`t exactly be catagorized under "open string vibrato".

I use both wrist and arm movements, depending on which string I am and what finger I`m using. O___o And sometimes the dynamic stuff also.

Which vibrato is better? Arm or Wrist? Because I`ve been trying to do arm but all I can ever do is wrist.

ok ok not "open string vibrato" but "artificial vibrato" happy!? =P... i dont know what i do... i used to do wrist... but then i couldnt do it anymore one day.. so now i do arm haha.

"Which is best... full arm or wrist?"

I use a full arm vibrato. I played viola for years and it served me well... now I`m playing mostly fiddle.. full arm still works very well on waltzes and slow tunes. I teach vibrato starting with the second finger... with your hand slid all the way up in position so that your hand is touching the shoulder of the instrument. Then... start by gently releasing (keep 2nd finger down) but relax hold on the neck... and just pull your hand/arm back away from the shoulder. Kind of a `touch-away-touch-away` feel. Keep it steady at a very slow tempo... over weeks gradually speed it up. It takes time... patience.
K
http://www.folkfiddle.com

open strings vibrato? YES! I am a guitar player originally who has crossed over to violin. I used a technique on violin that i stole from guitar to get vibrato on an open string. When playing the open string, take you finger and depress the string beyond the nut,{inside the scroll}

depending on your violin and finger size you may have more luck than others. I can only get it on the D, and A strings.{fat fingers, skinny scroll} Also the type of vibrato comes out as a weak eerie pitch bend, but anyways, it is an interesting move! and one worth investigating.

Also, there is a risk of slipping your string out of tune from the tension change on the pegs, but this is a matter of violin, make,string guage[thicker guage works better], and the amont of tension it will take. Give it a try, cheers!

When you`re playing an open string you can gently shake the whole violin, and it sounds just like vibrato.

Naw, you don`t have to shake it. If it`s a long note (say a whole note or half note), just take your First Finger and then lightly tap it where the string touches the first part of the fingerboard (where it is nearly right next to the tuning pegs). It should sound like a vibrato. I`ve stunned my Strings Teacher by doing this, but it sounds like a vibrato.

For Vibrato that you actually have to use your fingers, just rock your finger back and forth. It may take a while, but it`s best to start with about 2 whole rocks (back and forth) in one bow stroke. Then move up to 3, then 4, then 5, then 6, and etc. until it actually sounds like one. One method I use to practice is called "The Dying Cow". You place your First Finger, or whatever finger you want to practice and then place it on B on the D String (You have to shift) and then rock it back and forth. It sounds really nasty and if lots of people play it, it will sound like a chorus of dying bees.

how the hell do you do open string vibrato

First of all, if you shake your violin, you just vibrate the inside cavity of your violin, that`s all. That`s not really a vibrato.

The way I do an open string vibrato is...

Look at the pegs of the violin. You`ll see the strings touch on a little risen platform before running down the fingerboard; put your first finger there, right on top of the platform. Then, lightly and quickly tap the area. You can move down until you feel the space between the fingerboard and the string, but then it starts to sound like G sharp, E flat, B flat, or F natural (depending on the string)