>This is the problem I have at the store where I work...NO hunidity control, >big picture windows allowing sunlight/heat to focus DIRECTLY on SB's! Terry, There's your problem right there. Direct sunlight and humidity control are two VASTLY different things. When you were looking for explanations for this problem a while back, I don't remember you mentioning the direct sunlight. Did I overlook that? (wouldn't be the first time) >My conclusion from my poorly designed study is that it is important to >watch out for drafts (probably sun also) when tuning. The change in the >string seems to be quite rapid and is only ameliorated when the plate and >frame catch up. Larry and Terry, direct sunlight moving across a soundboard, plate, and strings will have an immediate and drastic effect on the tuning. Humidity changes occur over hours and days. Wood absorbs and releases humidity rather slowly, and at a rate proportional to the difference between the air moisture content, and that of the wood. If the moisture content of the air is considerably different than that of the wood, the wood will pass moisture faster than if the difference was slight. Wood at 12% MC will get to 8% MC faster in air of 3% MC than in air of 7% MC. A ten degree difference in room temperature for a couple of hours or so won't change the tuning nearly as much as five minutes in direct sunlight, even if it takes room MC way down, and in both cases it's the temperature change that makes the most immediate difference. In the long run, the humidity change will have about as much effect as the sun exposure, only it takes a lot longer. More perspective. Ron N
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