Try as I squint my eyes, I can't detect anything that would make acquisition mandatory. And I'm no particular Barts fan though if truth be told they sound good on three of my basses equipped with them: My fretless LP de Luxe, my fretless LP DC de Luxe and the Primavera one-off with the mandolin frets. The harshness on a regular fretted bass magically transforms into a "true-to-the-acoustic-tone"-sound on the fretless LPs; with the Primavera I suppose it is the different wood.
