One of the most valuable practicing techniques for general tone and bow control is practicing with open strings. There are an infinite number of ways to practice with open strings that will generate postive results. I recommend incorporating 5-10 minutes of open string practice into your daily routine. Here are some suggestions:
Definitions: Imagine that there are 5 points of contact on the string between the bridge and fingerboard, with contact point 5 being closest to the fingerboard, and contact point 1 being nearly on top of the bridge.
Practice all of these exercises on each open string, then with fingered notes in different positions.
Exercise 1 - Amount of bow stays constant; weight, speed, contact point change.
- Starting on contact point 5, play repeated full bows. Bow speed should be fast, bow weight should be light. Play until the sound is full and ringing and the string is vibrating widely from side to side.
- Repeat on contact points 4-1, still using your whole bow. Remember that as you get closer to the bridge the bow weight must get heavier and the bow speed must get slower.
- Practice on each string. As you get closer to the bridge, check in to make sure your right arm, shoulder, and hand are relaxed. No Pressing!
Exercise 2 - Weight and speed stay constant; contact point and amount of bow change
- Starting on contact point 1 in the middle of the bow, play right on the bridge using just an inch or two of bow. Weight will be very heavy, speed will be very slow.
- Continue playing and move to contact point 2. Weight stays the same, but you will be using more bow and a slightly faster bow speed.
- Continue to contact point 3. You will be using a full bow.
- Return to contact point 2, then contact point 1, gradually using less bow as you get closer to the bridge.
Exercise 3 - Son File
With your metronome set at quarter note = 40, play whole notes, practicing the following:
- Down bow diminuendo (f>p), up bow crescendo (p<f)
- Down bow crescendo (p<f), up bow diminuendo (f>p)
- Down bow diminuendo (f>p), up bow diminuendo (f>p)
- Down bow crescendo, up bow crescendo (p<f)
- Down bow and up bow hairpin (p<f>p) (f>p<f)
The goal is to expand your dynamic range, so that you play these exercises with the fullest forte and softest piano that you can. Practice producing these dynamics changes first using only bow speed, then only weight, then only by changing your contact point, then put them all together!