I think it has mostly to do with the bass and setup than the strings. I have used the same strings (TI flats) on all my fretless basses for the last 2 decades. Some basses have more Mwah than others. I think the flatness of the fingerboard is the most important, then the finish or hardness of the fingerboard and last the pickup. A bridge pickup is much better.
For many years before I used roundwound Rotosounds on my fretless basses with the same results. Some had a lot and some very little.
In my limited experience? I'd have to agree. I currently have 3 lined fretless basses, and here's what I've learned so far:
- 32" scale '93 Fury Anthem. It has a Pau Ferro fingerboard -IMO, not a good wood for a fretless fingerboard, but it looks pretty. And, since the guy that made it died in the late '90s, it's a little late to complain. It was made to wear tape wounds - the pickups screech like a banshee with anything else - and to sound as much like an upright bass as possible. Which, with a set of Roto TruBass 88 Tapes, it certainly does. If I play it correctly (like an upright), it "mwahs" very, very nicely...
- '24 G&L Kiloton lined fretless. Ebony fingerboard, and La Bella DTF4-A Flexible Flats. It's set up pretty "normal" for a 34" scale bass, and again; if I do my part, it "mwahs" quite well..
- '24 Schecter Stilletto Studio lined fretless. It came to me wearing EB Group IV Flats, and I have no desire to replace them. Ebony fingerboard; set up "normally". It "mwahs" at least as well as my other two. However...
With the exception of the Fury Anthem, I usually just play the other two fretless basses like I play all my fretted ones. Unless I know that a particular song I want to play, was originally played/recorded on an upright...
