@Iwan Roth said:
The "sul G playing" on violins is very often used in the standard literature of famous composers and is a very typical effect.
Then I must be really famous, because I tell the string players what strings to play almost 40% of the time. I also occasionally write in which valves to use for the brass, and fingerings for the woodwinds maybe 5% of the time. The brass with their unique structure of partials combined with their few valves, typically allows for as many as 5 permutations for each note getting progressively more dense in permutations on the upper ranges. And some fingerings against other fingerings can be so dramatic that just about anyone, even with untrained ears, can hear the difference. Of course I only write those in in slower passages where 1) it'll be heard enough to warrant it 2) it'll be reasonable enough for the player to use it.
As someone who is a multi-instrumentalist, I find it important "get involved" in the performance of my music by writing beyond simply just the notes, articulations, expressions, and dynamics. I have requested certain mouthpieces on occasion as well.
I grew up playing Violin, Trumpet, Flute, Piano, Drums, Clarinet and Saxophone, as well as synth (but of course).
I think, although definately unreasonable, that Violins (but maybe even more importantly teh solo violin) sampled such that every note within an octave or two between each and every string and back, would be great. It would give us MIDI guys the ability to have multiple choices for each note destination as well so that we could have the same line performed 4, 5 6+ times each, subtly different. But for those who know WHY to write "sul" any string, they're the ones who are going to understand how to use such an instrument to it's best. It is simultaneously something that affects performance and tone. As a composer I find the choice of string as important as the choice of harmonic fingering, which of course in real classical music MUST be specified.
Evan Evans