A super sharp notch (or band pass) filter would do very well. All you have to do is home in on the offending frequency and turn it down (most of the time a 6db cut is enough to tame even the most offending frequencies. You probably don't wanna get rid of it all together, but just make it less offensive).
is the guitar resonating? same pitch every time? is it only heard in the recording? only when using the mic? or do you hear it even when you are just playing the guitar in the room and not recording? which mic? if you have another guitar, do both guitars do the same thing? what recorder? do you have a parametric eq available?
are you sure it's not your room? if your room has a mode where you're hearing the overtone, especially if your guitar resonates at that same freq or a multiple thereof, you might have to treat the room. or try recording in a different room.
Man, don't EQ it out! You gotta' move your mic, swap out your mic, change positions in the room, change rooms, etc until you record it right in the first place. Leaning on EQ to fix it in the mix will never teach you anything, and never sound as good.
Man, don't EQ it out! You gotta' move your mic, swap out your mic, change positions in the room, change rooms, etc until you record it right in the first place. Leaning on EQ to fix it in the mix will never teach you anything, and never sound as good.