Several months ago I purchased a folk-size acoustic guitar. It's not top-of-the-line but it had quite a nice sound up until a few weeks ago.
Previously, it had a rich, resonant tone and was capable of substantial volume when played with a pick. At the present, there's noticeably less "depth" to its sound, particularly for the fifth and sixth strings. Higher notes on the sixth string sound particularly lifeless (fewer overtones?), although all strings sound worse (to varying degrees) than they did a month ago.
Could this change be attributable to low humidity? In the last month, it's been fairly dry in my home; I've also been transporting my guitar outside (in a case) in sub-zero temperatures at least once a week for the past three weeks. If low humidity is the cause, would using a guitar humidifier restore the instrument's original sound? I should note that there's no visible damage (e.g., cracks) on the guitar.