I bought a Spectorcore 5 fretless 6 weeks ago and was about to sell it. I could not get used to the B string.This is my 2nd 5 string and I had the same problem with the first, a G&L 2500 Trib. I wish I could keep everything, but it's stupid to have unplayed basses when someone else will dig 'em. A friend suggested to try dropping the B and adding a C. So I did and Boy Howdy, it's more fun than 2 beer hats. The strings on it currently are round wounds, but the C is a different make and sounds it(not too bad,though). My experience with fretless is less than my experience with 5 strings, but from reading through the forum flatwounds are the way to go. I would love to hear anyones advice on flatwounds on fretless basses or on EADGC for that matter. What I like about the current mystery rounds is their singing tone. I know that doesn't explain much, but let me know what you like. Oh, this is my first experience with a Spector bass so I really don't have any preconceptions there. Fenders, I'm an opinionated butthead about... And thanks!