These examples are here for the benefit of string players who have never been exposed to the two best long tone warm up exercises from the world of flute playing. They kind of serve as exercises and meditations. I love to get completely lost in the complicated acts involved in sound production and really clear intonation, and forget about what notes I am playing or where I am on the fiddle. On the flute I used to practice these at 60 to the quarter note. I like to practice them without a metronome (it distracts from the meditative experience) but I like to stay strictly in rhythm, filling out every note as completely as possible.
Spending quality time in the high register of the violin is kind of like re-connecting with what I always wanted to do as a flutist: make the flute sound like a violin. Now I'm trying to make the upper register of the violin feel and even sound like the upper register of the flute!