String crossing in thumb position

[Hector]

Hi chaps.

Inspired by my difficulties with this exercise (poor quality, but hope you can see it clearly enough):



I've been trying to work on string crossing (fifths and thirds mostly, with a few octaves when I'm feeling limber) in thumb position. Basically, my problem is that I don't know what the hell to do with my thumb most of the time! In the exercise pictured above, for example, it feels quite natural to have my thumb rest on the G string, but I sort of feel it ought to be on the D string behind my index finger.

Does anyone have any tips for this sort of thing? What should I do with my thumb when playing intervals across strings?

Any help would be greatly appreciated! I'm quite worried to suddenly find such a large gap in my playing ability....

H

[daflewis]

at first glance i'd have thought that you'd be using your thumb for the Eb's which would place it on the D string - is that not the fingering suggested?

[chrkelly]

It's Petracchi? Possibly the most annoying exercise in the world, but a really good one. The point is to keep your 1st finger stopping that Eb the entire way through the exercise, don't lift it at all. Take time to tune the other notes to that rock solid Eb. I'd keep my thumb stopping a D to help out the 1st finger. Fingering would be 1 3 2 3 etc in thumb position.

Then you could try Daf's fingering which would be T 2 1 2 etc making sure you keep stopping that note with your thumb. Starting in D would be easier for this one. You could check your D with the D harmonic to make sure your thumb isn't wandering.

Hope this makes sense

[Hector]

Thanks for the help guys.

[quote name='chrkelly' post='913657' date='Aug 3 2010, 11:06 AM']It's Petracchi? Possibly the most annoying exercise in the world, but a really good one.[/quote]

Emphatic yesses to all of those!

Daf, although playing the Eb with the thumb would be one solution (and one I'd probably use), the exercise calls for it to be played with the index finger.

I guess I'm mostly just confused about the role of the thumb in thumb position (which, upon reading sounds really daft). I'm using at the moment in a supportive manner, with all the fingers closest to the nut down behind all the others, as would be the case in lower positions. I'm guessing that it's just gonna take a little slow and careful practice. My fingers are flattening out too, so I'm gonna take extra care over this stuff and get a solid foundation.

I've neglected the thumb playing recently, which is probably why I'm getting whupped so resoundingly by Signor Petracchi....

[daflewis]

Ah, fair enough... but, YUCK! that's proper medicine that is! - horrible, but good for you!... must give it a try....

[Damo200]

I've got a spare copy if you want it Daf he he.

Thats the girls version anyway - do 'the mans' octave one! Oh, and Hector don't worry about your thumb. Just keep EVERYTHING relaxed, with particular eye on your bowing arm as the tension always begins there.

Best regards brave soldier.

D