actually, when recording acoustic guitars you tend to get this god awful low drone if you don't EQ it out. Typically its below 100, and if you can, you might start rolling it off starting at 150.

If you can't, you might try changing the placement of the mic from right on front to possibly closer to the neck or where it sounds best(if that's what you are using) or if you have controls onboard the acoustic to turn down the lower range.

I assume you are talking about the drone on the first beat, and if it's not that then I misunderstood and you might know this already.