Put some new Martin custom light bronze 80/20 (.011-.052) and they are buzzing like crazy. Any opinions on these strings?
I've used (Acoustic) Martin Custom Lights before and currently trying out the Extra Lights. I've been happy with both (though will probably go back to the Lights or even Mediums just to get a bit more fullness).
I suppose some more info is needed such as:
:?: Buzzing everywhere (ie. irrespective of which fret you're at)
:?: Tuning (eg. alternate/standard).
The only thing I can think of - by taking a wild stab in the dark - is maybe the tuning is not at the correct octave (ie. you might have EADGBE tuning but maybe it's down an octave thereby suggesting the strings are slack). :?
From little things big things grow - Paul Kelly
If you had heavier strings on before, they had more tension on the neck so there was more of a bow. Now, with the lighter strings, the neck doesn't have the tension and is less bowed so the truss rod probably needs adjustment. If you are uncertain how to do this, take it to a shop and have it setup by a professional. Everytime I try to do it, it takes me days to get it right.