It's the little things.

[BlueBowman]

Every year around this time, without fail, the relative humidity drops overnight in my climate controlled music room by ~10%. My guitars all sound like they opened up over night -- more resonant and musical. It's not always subtle, and today was one of those days. I grabbed the Larrivee 000 today, and the first note just bloomed like never before. Ah, I knew immediately, but I checked one of my hygrometers to verify the drop. Right around a ten percent change, as usual. That was a fun playing session.

Little things like that seem to mean more to me these days 

[B0WIE]

I do notice that around 10% below ideal can give a nice, crispy tone. The older guitars seem affected less but the ones less than 20 years old can really sparkle. With the way my setup has been in the last few years they never see below 37% so I haven't experienced that in a while.

[BlueBowman]

I do notice that around 10% below ideal can give a nice, crispy tone. The older guitars seem affected less but the ones less than 20 years old can really sparkle. With the way my setup has been in the last few years they never see below 37% so I haven't experienced that in a while.

That's exactly it. Yesterday it dropped from roughly 60% down to 50%. It's always that first drop when I typically hear the most change. And, like you point out, it doesn't seem to happen so much with older guitars. If memory serves, I think those older guitars exchange less often with the environment than newer ones. Older wood seems to be bit more impervious, for whatever reason. An interesting topic. Might also be the reason older guitars are less susceptible to humidity-related cracks.

[B0WIE]

That's exactly it. Yesterday it dropped from roughly 60% down to 50%. It's always that first drop when I typically hear the most change. And, like you point out, it doesn't seem to happen so much with older guitars. If memory serves, I think those older guitars exchange less often with the environment than newer ones. Older wood seems to be bit more impervious, for whatever reason. An interesting topic. Might also be the reason older guitars are less susceptible to humidity-related cracks.

That's as I understand it. The cellular structure has oxidized and hardened to the point that it's slowing moisture exchange.
60 to 50 must be a big shift for you. The highest I let it go is 50. The few times I've had it at 60 I could really hear it. Not trying to sound snobby, in case it comes across that way, I know everyone has their own humidity challenges.