I was fortunate enough recently to attend a concert by the Artis-Quartett Wien. My friend and me got seats in the front row and were bowled over by the performance. I brought my sketchbook with me and drew the group while they played - I think I went through about 17 pages. It was an awesome experience and a huge challenge to try to capture the motions of the musicians. Afterwards we got to meet the quartet and get their autographs.
(From left to right, Peter Schuhmayer, 1st violin; Johannes Meissl, 2nd violin; Herbert Kefer, viola; and Othmar Müller, violoncello.)
Here are some of the better sketches from the night-