I like the GHS flats but I had a weird problem with one this week. I noticed that the G and F on my D string were out of tune. I checked the open D string and the tuner and my ear said it was fine. The tuner thinks those two notes are in tune too but my ear says they are a quarter step or so off. I don't know how that can be. I'd like to do a search on this problem but what would I search on? Does it have a name? Searching on "out of tune" won't get me anything useful or if it does the useful stuff will be lost in the tons of normal tuning problems.
I guess even flats wear out or break. These weren't very old, only about a year but I'm not upset or dissing the product. Changing strings once a year is no big deal even if flats users normally never change them!
Might be an intonation thingy? Dunno. My tuner says my A on the E-string is off, too. By ear, it doesn't sound like it.
So might be your tuner reacting to overtones or something as well.
