Vince, Thanks for the real life example of the effect of Damppchaser system installation. With respect to your comment that variances in humidity might have limits, I generally disagree. It's a complex issue, because just coming up with an annual variance figure doesn't really give the full picture. As you state, often the major humidity change occurs "between seasons" (which I'll interpret as being most commonly over the summer). But even taking that to be the case, meaning (usually) extraordinarily sharp pianos to be pitch-lowered in the fall, exactly how extreme the change is will "echo" through the fall semester. In my situation, we have a typical rise of 50% between April and August, leading to _major_ pitch lowering of every single piano (20 - 50 cents is normal, meaning that range on every single piano). If all the pianos are pitch lowered and fully tuned by the beginning of the semester (I wish), four weeks into the semester, after the humidity has dropped its typical 10 - 15%, every piano needs a pitch raise and full tuning. And again more or less every month until humidity reaches and stays at bottom. To keep faculty piano studio pianos in adequate tune would require weekly full tunings (the piano profs and students suffer). And of course there is also the issue of "micro" changes, within one day, week to week, depending on weather (how much is the heating system being used, how humid is the outside air which is being brought in to do air exchange: a rain storm after a dry period has resulted in a 15% rise in humidity over a period of a few hours in a couple instances I have measured. Leading to virtually every unison on the concert grands being "out of tolerance.") As I look at it, it isn't so much a question of workload per se as one of quality. Places with lousy humidity control learn to live with lousy tuning to one extent or other, because no place can afford what it would take to keep tuning up to high standards (or if they do, it is probably limited to very specific pianos). Bottom line is, if you want quality, you have to have at least some degree of humidity control. I really don't think the current multiplier for high variance (0.4 for 50% plus) adequately reflects the theoretical workload need. But maybe it's extreme enough to get attention. Regards, Fred Vincent Earl Mrykalo wrote: > > Fred, et. al., > I would like to comment on the humidity variance factor. I have found that > before dampp chasers were installed in piano faculty studios, to adequately keep > them in tune, I did full tunings on them every two weeks. With the systems > installed, I would go in every week and just tweak the tuning (10 min.), after a > full tuning once per month. We have humidity swings of about 30% on average. > This works out to be 9 hours worth of work per semester before the dampp chaser, > and 6 hours after it was installed. > It seems to me that more than 30% humidity variance would not have necessarily > increased the 9 hours, because the brunt of the changes would happen between > seasons. So I think that variances in humidity may have its limits. > vince
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