QUOTE(elisabeth_rb @ May 25 2007, 12:21 PM)

QUOTE(Miss Ross @ May 25 2007, 11:28 AM)

but I think they're looking for improved tone quality and this is often improved, for example, by not playing on the E string, but playing in 3rd position on the A.
Is this true of viola too, with the D and A strings? I've noticed that the A string notes often sound strained in comparison to the D ones. Maybe it's just my poor playing and maybe I'd like a brighter sounding A string when time come for re-stringing. Who knows??
The E string on the violin is especially bright, so I don't think the same 'avoidance' needs to be taken on the viola A string.
The key thing about keeping tone quality is to keep it similar in a phrase of notes, where you may choose to play the phrase all on the same string if possible.
There is also a certain timbre about the G string that is sometimes required to add to a piece tonally (the famous 'Air' for example), and of course viola players will similarly wax lyrical about their C string which can be particulalrly cello-like in a good instrument. Composers will write 'sul G' if they want the section all played on the G string for this effect.
And also of course it may have nothing to do with tone, but can be really helpful in avoiding nasty string crossings.
Isn't it wonderful to have a choice about where to play a note. Many instruments don't have that.