I believe every acoustic guitar has its own resonant frequency. When tuned to a certain pitch, it sounds better. Play with yours at varied ranges from A=432 to A=444. Somewhere within that range, it will sound "better" to you. Once you get outside of those ranges, you're into a "half step down or up" and I believe you're looking at open tunings, which aren't using the same string tensions equally across the neck. It's one of the reasons I love open and altered tunings so much. And why as a solo instrument, it's so versatile.