I'm currently practicing some sweep picking arpeggios, and I was wondering if it was hurting my technique to move my fretting hand's thumb around during different parts of a single arpeggio.
I play with the thumb on the back of the neck (instead of the "baseball grip"), and I feel more comfortable moving it around sometimes as some parts of the sweep are hard to reach.
Will moving it around make the technique less transferable to other sweep picking shapes?
With sweep picking, as soon as each note has been played, it is muted, so it doesn't bleed into a whole arpeggio with notes sounding together. Sometimes it's done just with fingertips releasing, sometimes the thumb needs to help release fretting pressure, so, no, move it where it's needed.
short answer: no.
long answer: it depends
the position of the thumb behind the neck isn't as important compared to the orientation of your wrist. rather the thumb should be able to support any position required to facilitate proper wrist orientation. as long the thumb isn't exerting excess pressure (really it should just sit there), and isn't in an uncomfortable or strenuous position your good. let the thumb move to where it needs to.
im currently working on a sweeping passage with lots of position shifts. in a case like this the thumb NEEDS to move around quite a bit. as long as your relaxed the thumb should move quite naturally actually. just make sure its not moving around more than an inch or 2 if you're staying in one position.
