Hello all. My teacher has vastly improved my bowing technique compared to how it used to be. I can now produce an nice, even sound when playing long notes. My problem is that I still have trouble bowing quickly, i.e. playing eighth or sixteenth notes. When I bow with my metronome at higher tempos playing eighths or sixteenths I'm getting a scratchy and very unclear tone. Does anybody have any tips on this matter? Very much appreciated.