I need a truss rod adjustment? I just got my replacement acoustic bass today and I can't get it to hold standard tuning, I'm really thinkin that I'm gonna bring it to the shop but this would be the second time I've had trouble with this kind of bass, might be the strings, D'adario flatwound, they work fine on my electric fretless, but not the acoustic?! It came with corewound strings of fretboard doom on it. its a longer scale, so that might be part of the difficulties. Figured I'd pick at yer brains.
I didn't think most acoustics even had truss rods, although I'm pretty green on acoustic instruments.
With the problem you described, I wouldn't think of the truss rod, unless you are experiencing fret buzz or action too high.
Sounds like maybe the tuning pegs aren't holding the strings tight, so they are maybe slipping a little, causing the bass to go out of tune? Or is it more of an intonation issue where you tune it perfectly, but the strings sound sharp or flat as you go up the fretboard?