Because the fiddle has multiple strings, you need to understand how to get the bow from one string to the next properly (and smoothly). What most people do when crossing strings (moving the bow to a different string) is use their big muscles (again!) instead of keeping the arm muscles relaxed.
Here’s how to cross strings properly:
Set your bow at the contact point of the strings and position your elbow with the height of your instrument.
Stay on the D string first and practice moving the bow back and forth to create a sound on it, making sure the height of your elbow stays put.
When you start moving the bow, the elbow only moves 1 inch when coming to and from the frog. The only time the height of your elbow should change is when you actually switch strings, which you don’t do until the next step.
Now move your bow plane (angle at which the bow is at in comparison to the strings) over to the A string by moving your entire arm downward.
Use your index finger to help keep the bow hair in the same spot when you move to the A. Your A string elbow position should be in between where your D string elbow was and where your elbow would be if it were at your side.
Credit: By Rashell SmithPractice moving your entire arm up and down to move the bow plane from D string to A string.
Think mostly about moving your elbow to the proper position when doing this step. Don’t change the bend of your wrist at all to move the bow plane.
Move the bow back and forth four times on the D string.
Each one of these movements from contact point to the tip is called a bow stroke. Think a lot about previous fundamentals and try not to hit any string but the D.
Now quickly transition the bow plane to the A string using your entire arm.
Your elbow should have moved downward.
Do four bow strokes on the A string, thinking about moving the bow with bow fundamentals in mind.
Move the bow plane back to where it was for D. Repeat from Step 6.
The incorrect way to do this drill is by using your wrist instead of your entire arm as a system to change strings. Doing so causes more inaccurate string changes, so you definitely want to make sure your elbow is moving to change strings and not your wrist at this point.
In the future, there will be times when moving your wrist slightly to change strings is helpful, but it’s not recommended at first. You want to first establish a solid foundation of switching strings with your arm, and later you can get help with your wrist in fast passages. For now, just make sure you’re changing crossing strings with your elbow and not your wrist.
Here are some things to look out for when changing strings:
Make sure that your instrument is level to the ground and that you’re holding it properly.
Keep the bow away from the fingerboard because it’s harder to stay on only one string the closer you are to the fingerboard.
Don’t dip your elbow when you’re bowing on the D or A string. Only change the height when you change strings.
When crossing to the D or A string, don’t have a tense arm. Keep your upper bicep relaxed, especially when you start the stroke.
Don’t use just your wrist to move the bow plane up and down. This is the one time where using your arm is necessary.
Don’t change your bow grip when moving the bow plane up and down. Everything is guided by the arm system, and you shouldn’t be forcing it by pressure in your hand.
Don’t cut off the bow stroke short. Make sure you get to the tip with each bow stroke and try to follow as many of the proper moving and transitioning techniques as you can.
Avoid crossing slowly. You can create a bad sound by being in between strings too long.
Make sure you understand that changing strings, moving the bow, and transitioning the bow all require different techniques. When you find the proper bow plane by changing strings, it’s all about moving the bow and then transitioning the bow.
Although you use your entire arm in the crossover, that doesn’t mean that your muscles should be tense while changing positions. Think of it like this: If you were told to raise your hand up, you wouldn’t flex your muscle as hard as you could to help you achieve that movement, right? The same concept applies to crossing strings.
There’s no advantage to going slow through this process. You want to get out of that in-between elbow position as quickly as possible or the fiddle will sound bad when crossing from one string to the next. It works much better to move as quickly as possible, while not tensing up your arm, of course. You don’t want your arm to be tense when you move the bow from one string to the next.