The soundboard of our 2007 Yamaha C2 appears to be in good condition; I do not see any cracks, nor any separation between the glued individual boards that run diagonally. Is there a problem when you can see a very slight indication in the finish as to where the boards are joined? It's hard to keep the humidity from fluctuating when it bounces between 75% - 99% outside for long periods of time during the summer in Connecticut. We have central air, but it doesn't run constantly. We keep the temperature at about 76-78 degrees F. We also have a Dampp-Chaser humidifier/dehumidifier installed. This degree of concern is probably just my paranoia. ;-)