Trial Sounds

I really like violin sound.
I often visit a homepage of a music store which sells strings only, and download the violins sounds. They put trial sounds and comments for each violin on the page and because they are played by one good violinist, we can listen the good sounds of each violin (I can't distinguish the difference though).
Anyway, when I'm tired, I often listen these sounds and feel refreshed.
It's said that the high pitch sounds are good for brain. I feel it is true.