In response to the discussion between Tilman and Dennis, quoted here:
> On May 28, 2017, at 9:00 PM, HPSCHD-L automatic digest system <[log in to unmask]> wrote:
>
> Le 28/05/2017 12:07, Tilman Skowroneck écrit :
>> In Bremen: depending on the year, and if I don't watch out, it can fluctuate between 30% in early February and 85% in August.
>> In West Sweden: between 20% in February and 80% in the summer.
>>
>> It's mostly about how many frost days there are and how long those periods last. The high average for January here in the Borås area is -1 and the low average -6. Paris with a January (total) average of plus 5 is a whole different story.
>
> Thanks, Tilman. This is indeed much more variation than we have here. In
> the winter, I never let the RH go below 45%. (In the summer, I'm afraid
> I don't really know, but I'll have a closer look.)
>
I think that those who claim that the humidity swings are not a serious issue, as we see in this conversation above, don’t really realize what some environments impose on harpsichords. I have an instrument in Boston made a few years ago after the Hudiksvall Mietke. Instead of the Skowroneck lifters, it has conventional screw-operated elevators, allowing one to move the entire action up and down. In the summertime, right about the time of the Boston Early Music Festival, the humidity there can easily approach 80% or even higher. Ok, then, a couple of winters ago, right around Christmas time, I got a message from the owner of the instrument saying that they were having some minor problems with leaky dampers and rather poor repetition on the back 8’. I asked about the environment. The answer? The instrument was at Mechanic’s Hall, and the relative humidity had, that afternoon, been measured at 7%. I submit that no amount of fine workmanship or careful design is going to prevent anything made of wood from changing in height well more than the approximately 1mm in height over a full width of case parts of around 9-10” that it takes to throw the vertical relation of jack to string all to hell and gone.
Of course, in the case above, the elevators were dropped a bit, and all was well, but, as is so often the case with such adjustible stuff, nobody raised things up again in the summer when I next saw the instrument. It seemed slow and sloppy to me, and when I looked closely, I discovered that the plectra of the back 8’ jacks were sitting around 3-4mm below the strings. And because folks don’t keep close track of the adjustments they have made, we had to bring everything up by trial and error until the plectra were JUST below the strings, actually faintly touching them, on BOTH ends of the action, and then drop it down by my originally-intended distance for the back 8’ of, oh, I dunno, I guess it was a hair over 1mm or so.
With the Skowroneck lifters, it would all simply have tracked itself up and down from the top of the bellyrail.
owen
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