Like baz says - plus, if you have really flat frets (as in someone leveled the frets and took them down quite a bit without crowning them) the flat tops can 1) create intonation problems (because the string is not breaking over the fret near the middle and 2) create buzzing that isn't related to one fret being lower than the other but by the string breaking at the "back" (headstock) side of the fret and then "squirming" against the rest of the flat fret.
Thanks. So, if I understand correctly, when looking at the fret wire from the side, it should have a radius from one edge to the other with no flatness present. Is this correct?
Thanks. So, if I understand correctly, when looking at the fret wire from the side, it should have a radius from one edge to the other with no flatness present. Is this correct?
Pretty much so except in the case of an old vintage instrument with bar frets. Those sometimes tend to be a little flat on top but are very thin compared to modern frets.
A touch of flatness isn't incredibly unusual - especially if someone has been trying to deal with a fret buzz without having the proper tools to crown the top - but if it's pronounced it could be trouble.