Last week I received a used Mike Lull Fretless which had been converted from a fretted bass. From day one it had that fretless "muah" that would not quit. That's the problem, its too much. The Lull is an M4 with bartolini soapbars, Cocabola board, I do not know the brand of the strings but they are roundwound and look to be a light guage. The nut was originally cut too high and I have cut the nut down so that it has about a business card of clearance at the nut, which is more than my Pedualla fretless has. This excess and uncontrolled Muah was present when I received the bass, before and after cutting the nut and after adjustments to the neck tension and hight of the saddle. The actual play of the strings is now low action and normally where I play my Pedulla fretless. By way of contrast, when I play a Pedulla string, the sound is a constant singing which varies in intensity with how hard I strike it. Sometimes when striking the Lull string it seems that the Muah is delayed for a small fraction of a second and uncontrolled, almost as if there are multiple vibrations going on. In the Pedulla the degree of muah is controllable by how I play. The Lull is always inconsistant and it is so, up and down the string. The principal culprits are the E and A strings. Anyway, I seem to remember that light guage stings and round wound strings produce more muah on a fretless. I was going to change the strings to flats or half rounds but I wanted to see if any of you had any ideas. Its the inconsistant and delayed Muah that concerns me the most. It is hard to describe a string sound, but hopeully you get the idea. Thanks for any help you can give me.