What are the advantages/disadvantages? Do i have to adjust the truss rod in my guitar if i change the strings from roundwounds to flatwounds even if i use the same string gauge?
I put a set on my Ibanez 7 String once, I didn't tweak the truss rod at all (probably should have done, but I didn't), but they were nice to play on, no finger noise, really smooth.
I use them on my archtop. I really like them. They are not as bright as standard wirewound but they are so smooth and no finger noise. For jazz and old rock-in-roll they are great.
I use D'Addario Chrome flatwounds on my electrics and Half Flats on my acoustics. I hate the feel of round wounds and string noise. I went on to D'Addario's website, and there is no significant difference in tension between rounds and flats from what I saw.
I use the D'Addario Chromes too and the are much smoother. You can do those great 20 fret bass slides with them!! Bending is the biggest disadvantage... it's much tougher to do... at least it feels that way to me. I use them on my Jazzmaster because I wanted a "less-bright" tone and they do deliver the warmth. I really do love the sound of them but it is much tougher to rip a lead. As far as tension goes I'm not really sure... when these go I am going to try round wounds and see if there is a big difference in setup issues. I'm sure I'll know right away... that Jazzmaster floating trem is sensitive!!!