William! I see you in this video!! Hi!!! So I have some advice for you, but please see my comments today on your Yiddish tune regarding vibrato, because they are relevant to your scale work.
Tackling a three octave, multi-position scale is a brave and wondrous feat! So I congratulate you to begin with! If you were studying in my studio, I would ask you to slow down and play each note very carefully with lots of bow, no vibrato. Careful intonation, good tone. After that, you can started adding slurs and speed, but not until the intonation is spot on.
Aside from that I would address what the violin hand thumb is doing during shifts. Where is the thumb in third position? It is in a similar ‘shape’ related to the hand, as it is in when you are in first position. Good. Now when you travel to fourth, fifth, sixth and realms beyond, the thumb should come more under the neck for each higher position, a little further under the neck. Bring the elbow well under so the fingers can stay rounded and not reach out for notes in higher positions. Know what position you’re in, and where the thumb belongs in each position.
One good practice to help with this is shifting from the old position to the new position, then in reverse. So you are starting in third position, and then, when you reach the A string, you are shifting on first finger into sixth position. So let’s address that shift, because you are leaving your poor violin thumb behind in third position. I would make up a ‘unit’ to practice the shift and train the thumb. Start by playing all the A string notes in your scale.
(Fingering: On A, starting in 3rd position — Play and hold down 1, 2, 3, shift into 6th on 1, Stop). What does the thumb do during this segment? Let’s narrow that unit down to the shift alone, so we can see what the thumb is doing, then train the thumb to move with the left hand during the shift.
(Fingering: On A, starting in 3rd position — Play 1, shift 1 slowly, sliding into 6th on 1, Stop. Play 1 in 6th, slowly, slide shift 1 back down to 3rd) That’s yours to master, William! As you shift from third to sixth position on first finger, make the thumb come under the neck so the pinkie could reach if you wanted it to sit on the string. Slowly slide back, hearing the slide, seeing the thumb smoothly return to its place in third position.
So now I remember why scale practice is sort of my nemesis! Scales require all these added techniques and if you’re not doing them, it shows. You have to isolate the problems, in this case, shifts… and conquer them one by one! Good work, and good luck William!