Seasonal pitch change: was -- Long term pitch drop, was: Type O

[Ron Nossaman]

> Agreed. My speculation is that it is at best very little of the major 
> components that cause truly massive seasonal shifts in, e.g. spinets. 
> Not that we care so much about stability of these pianos, but they are 
> maybe worth looking at more closely just for the mechanics. Here in 
> Chicago, among my clientele (and yes, I still tune a few spinets), these 
> pianos move regularly between 435 and 445 even with my attempts to 
> "float" the pitch. The older they are, the more "volatile" they get. Is 
> this pinblock movement? Maybe to some wee degree. But I can't believe 
> that it would account for the large-scale pitch movement.

I unfortunately still tune a few spinets too, and can 
sympathize. I also doubt that pinblock movement could make 
that kind of difference, but I still think it's contributory.


> All true. Especially the voodoo. Until we have data, that is. And yet, 
> there is still measurable bearing change at the bridge from season to 
> season. This in no way argues for "rise and fall" but certainly some 
> movement of the major structures that correlates with pitch. It could be 
> any and all (I suspect the latter) of the things you mention above, 
> although there are some forces which oppose rather than complement.

I'd say all, to infinitely varying degrees.
Ron N