I was experimenting with spectrum analysis of guitar plucks and this is what i got on an open low E recording:

As you can see the strongest peak is at about 247 Hz, which is a B3 while the peak at about 82 Hz (E2), which should be the fundamental frequency of the string is only the second one. Whay is going on here? Is there something I missed?

Please excuse me if I posted in the wrong place.