Due to lack of funds I've kept the same set of Helicore Hybrid Mediums on my bass since I bought it. They've been on there about 5 years, with 2 years of really intensive playing. Lately they've developed a really awful wolf tone between G-A. No amount of adjustment of the ferrule can get this to go away. The strings are bright and still speak fairly well, but this warble is driving me nuts. My question: is this the strings going bad? I was set to wait until the strings sounded dead or fell apart before changing them, but they still sound as bright as ever and play much the same. Anyone else have any experience with this? P.S. I play about 90% arco, 10% jazz pizz.