Should I use them or take them off. They are currently on my strings, but my two lower strings sound really bad.
The purpose of these plastic tubes is to prevent your bridge from being damaged. As we violinist know,the violin needs constant tuning and if you are using gut strings,would react weirdly to the physical environment should it change. The plastic tubes are to prevent your bridge from being cut by the strings especially by the E string which is very thin.Normally I take off the plastic tubes on the lower 2 strings but I think its okay if you don't too. I don't think it will affect the sound though.Maybe your strings are new so they haven't really settled down yet.Different strings when placed newly create all sorts of odd sounds.I particularly hate the Dominant ones as they have that metallic edge in the sound when its just placed.
I don't know what they're called and I don't play violin but I've seen them. They fit on the string where it passes over the bridge. I usually see them on the E string and I suspect it's to control the shrill highs. If they sound bad on your instrument, don't use them.
