Would you tell me/us what are your favorite strings?
Pyramid Pure Nickels 45-105 are my favourite roundwounds. They age better than most roundwounds IMO and once they're broken in (which may take weeks or even months depending on how much you play) they have a warmer, fatter tone than any other roundwounds I've tried. I guess some might call them muddy when they reach this stage but for MY needs they are perfect. They don't have the tone/feel of flats but they AGE like flats in the way they just keep getting better and better.
GHS Balanced Nickels are also nice for a warm roundwound tone but they don't age as nicely as the Pyramids and the more supple round core feel doesn't work for me on all basses (particularly on short scale basses). They sound better out of the box than the Pyramids though.
Thomastik Jazz Rounds have an AMAZING warm and "woody" tone but the ultra-light tension means I always need to hold back a bit with my plucking hand so I only use them for studio work. On gigs I want to DIG IN and have fun.
I use other (and brighter) types of roundwounds too but I keep coming back to the Pyramid Pure Nickels. They are a bit on the warm/mellow side for some styles of music but for ME they're usually the first choice. When I want to go brighter it's usually Roto 55s/66s or Thomatik Infeld Superalloys. They will need a couple of sessions to get rid of excessive zing before I really enjoy them though.
When recording I actually use flats more often than rounds, unless the song really calls for rounds. Flats often sit better in the mix in my experience. LaBella DTF 760FL for old school thump. Thomastik Jazz Flats for a more "modern" tone with more sustain (the short scale sets are horrible though with an INSANE jump in tension between E-A). Pyramid Gold for "that" 60s tone but only with short scale basses, I don't like the Pyramid Gold long scale sets. The E-strings gets too extreme, thumpy to the point of being completely dead.
For reference (as I think this is crucial for any meaningful context):
I mostly play fingerstyle close to the neck and like to be able to dig in hard without sounding like an avalanche of scrap metal. Hence my preference for warmer sounding strings. My "reference tone" is a passive P with the tone rolled off a bit, just to the point where the tone starts to thicken but the upper mids are still present. I never use bridge pickups or blend pickups, that's just not my kind of tone. With two pickup basses it's neck only for me. I only use vintage tube amps, mostly with a "British" voicing. I use modern cabs but never Ampeg 810 if I can avoid it, I can't stand the midrange honk in those cabs. My favourite cab is a Bergantino 2x12. I mainly play 60s/70s/90s inspired rock (yeah, I bypassed the 80s, lol). Psych, prog, "alternative" rock. Sometimes heavier stuff.