Immediately after stringing, the string set sounds bell-like and fills the room. In the first three to five hours of playing, the strings feel a touch softer and sound a little warmer than they do for the rest of their lifespan. Then the strings open up, sound more brilliant and open, and feel a little tighter beneath the fingers. THOMASTIK DP100 the bell-like sound that fills the room decreases slightly in the last third of the strings’ life and they sound more direct – from this point on, the tonal character of the strings barely changes.