Jane the plywood violin sounds really good today. Vanessa the Cecilio 650 has good tone but when playing, the note breaks into a flat. This has happened many times in the past and I just replace the strings, but the strings on Vanessa are fairly new Tonicas. I have not heard any reviews on Tonicas that would suggest they have a short life or that they have this tendency to break their tone. My question: is there some deficiency in my setup that could possibly cause this to happen? It is not my playing nor the FM bow I'm using. I'm not pushing too hard nor too soft. I'm baffled. I play a tune on Jane then immediately play the same tune on Vanessa, so I'm pretty sure it's not me. Any ideas?