I've tried to change my TI flats on Squier VM Fretless to Rotosound roundwounds and got almost "fretted" sound. No mwaah. Far away step from Jaco tone. Flat were more worm and mwah-ish
You need to make the mwah sound with your left hand, roll your finger into the note a little. Also, use only the bridge pickup and don't play too hard. Also, the strings might need to be worn in a bit first, Rotosounds are really bright at first.
Should I lower the bridge saddles? Flats are much easier to get the great warm mwah-sound BTW, Rotosounds are nickel.
I'll try putting roundwounds from my fretted bass, when they worn a bit. Thanks, iunno, for idea.
Plus, if you just put the rounds on after the T-I's, you are most likely going to need to tweak the neck a little bit to compensate for the higher tension.
Yes, I've ajusted neck after installing rounds. I think the main thing for me is to set really low action, which is maybe a problem. Fingerboard surface isn't smooth enough (is causes some buzz on low action) and bridge is gotoh 201b, which won't produce a really low action. Maybe neck shimming or another bridge saddles?