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And now, as the bow moves, we see the main problem is that the bow is traveling parallel to the floor, definitely not at right angles to the string. There are two causes: the bass is leaning at too much of an angle (although contact with the body is about right), and the elbow is still bent, rather than straightening as the bow nears the tip. Both of these flaws need to be adjusted, the angle of inclination by lowering the endpin, to make it possible to have the same contact point with the body.